Attachment 357839 Details for Bug 192933 – Patch

[patch] Patch

bug-192933-20181220113900.patch (text/plain), 218.97 KB, created by Chris Dumez on 2018-12-20 11:39:04 PST

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Creator: Chris Dumez

Created: 2018-12-20 11:39:04 PST

Size: 218.97 KB

patch

obsolete

>Subversion Revision: 239428
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index 7017533c8041959ca35a2379a31888c0a0a4525c..107afd035568c57d5d12430b3681ac0de989b185 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,19 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm:
>+        (Inspector::RemoteConnectionToTarget::setup):
>+        * inspector/remote/glib/RemoteConnectionToTargetGlib.cpp:
>+        (Inspector::RemoteConnectionToTarget::setup):
>+        * parser/SourceCodeKey.h:
>+        (JSC::SourceCodeKey::SourceCodeKey):
>+        * wasm/js/WebAssemblyModuleRecord.cpp:
>+        (JSC::WebAssemblyModuleRecord::link):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
>index 64ddbd43e28acba272971e9f358e2b6444a5bc2e..8740991b76184a7e3a60b424a18f1a5ffddbbbd5 100644
>--- a/Source/WTF/ChangeLog
>+++ b/Source/WTF/ChangeLog
>@@ -1,3 +1,13 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * wtf/Optional.h:
>+        (WTF::Optional<T::valueOr const):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 2ab911fdf7cb3446e56afa8f49fdbccd53859356..8e0576f2fc06cc6a1072214d4f762dfd2b2b9670 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,296 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * Modules/applepay/paymentrequest/ApplePayPaymentHandler.cpp:
>+        (WebCore::convert):
>+        (WebCore::ApplePayPaymentHandler::didAuthorizePayment):
>+        * Modules/encryptedmedia/MediaKeySession.cpp:
>+        (WebCore::MediaKeySession::load):
>+        * Modules/indexeddb/IDBDatabaseIdentifier.h:
>+        (WebCore::IDBDatabaseIdentifier::hash const):
>+        * Modules/indexeddb/IDBFactory.cpp:
>+        (WebCore::IDBFactory::open):
>+        * Modules/mediastream/MediaStreamTrack.cpp:
>+        (WebCore::MediaStreamTrack::applyConstraints):
>+        * Modules/mediastream/RTCDTMFSender.cpp:
>+        (WebCore::RTCDTMFSender::insertDTMF):
>+        * Modules/webdatabase/SQLTransaction.cpp:
>+        (WebCore::SQLTransaction::executeSql):
>+        * Modules/webvr/VRFrameData.cpp:
>+        (WebCore::VRFrameData::update):
>+        * animation/AnimationTimeline.cpp:
>+        (WebCore::AnimationTimeline::updateCSSTransitionsForElement):
>+        * animation/DeclarativeAnimation.cpp:
>+        (WebCore::DeclarativeAnimation::cancel):
>+        (WebCore::DeclarativeAnimation::invalidateDOMEvents):
>+        * animation/KeyframeEffect.cpp:
>+        (WebCore::computeMissingKeyframeOffsets):
>+        (WebCore::KeyframeEffect::applyPendingAcceleratedActions):
>+        * animation/WebAnimation.cpp:
>+        (WebCore::WebAnimation::runPendingPlayTask):
>+        (WebCore::WebAnimation::runPendingPauseTask):
>+        * bindings/js/SerializedScriptValue.cpp:
>+        (WebCore::CloneSerializer::write):
>+        * crypto/algorithms/CryptoAlgorithmHMAC.cpp:
>+        (WebCore::CryptoAlgorithmHMAC::generateKey):
>+        (WebCore::CryptoAlgorithmHMAC::importKey):
>+        * crypto/gcrypt/CryptoAlgorithmAES_GCMGCrypt.cpp:
>+        (WebCore::CryptoAlgorithmAES_GCM::platformEncrypt):
>+        (WebCore::CryptoAlgorithmAES_GCM::platformDecrypt):
>+        * crypto/gcrypt/CryptoKeyRSAGCrypt.cpp:
>+        (WebCore::CryptoKeyRSA::importSpki):
>+        (WebCore::CryptoKeyRSA::importPkcs8):
>+        * crypto/keys/CryptoKeyRSA.cpp:
>+        (WebCore::CryptoKeyRSA::importJwk):
>+        * crypto/mac/CryptoAlgorithmAES_GCMMac.cpp:
>+        (WebCore::CryptoAlgorithmAES_GCM::platformEncrypt):
>+        (WebCore::CryptoAlgorithmAES_GCM::platformDecrypt):
>+        * crypto/mac/CryptoKeyRSAMac.cpp:
>+        (WebCore::CryptoKeyRSA::importSpki):
>+        (WebCore::CryptoKeyRSA::importPkcs8):
>+        * css/CSSComputedStyleDeclaration.cpp:
>+        (WebCore::counterToCSSValue):
>+        * css/CSSFontFace.cpp:
>+        (WebCore::calculateItalicRange):
>+        * css/CSSPrimitiveValue.cpp:
>+        (WebCore::CSSPrimitiveValue::doubleValue const):
>+        * css/CSSStyleSheet.cpp:
>+        (WebCore::CSSStyleSheet::addRule):
>+        * css/DOMMatrix.cpp:
>+        (WebCore::DOMMatrix::rotateSelf):
>+        * css/DOMMatrixReadOnly.cpp:
>+        (WebCore::DOMMatrixReadOnly::validateAndFixup):
>+        * css/StyleBuilderCustom.h:
>+        (WebCore::StyleBuilderCustom::applyValueCounter):
>+        * css/parser/MediaQueryParser.cpp:
>+        (WebCore::MediaQueryParser::commitMediaQuery):
>+        * dom/Document.h:
>+        (WebCore::Document::referrerPolicy const):
>+        * dom/Element.cpp:
>+        (WebCore::toScrollAlignment):
>+        * dom/EventTarget.cpp:
>+        (WebCore::EventTarget::addEventListener):
>+        * dom/MutationObserver.cpp:
>+        (WebCore::MutationObserver::observe):
>+        * editing/cocoa/FontAttributeChangesCocoa.mm:
>+        (WebCore::FontChanges::platformFontFamilyNameForCSS const):
>+        * fileapi/File.cpp:
>+        (WebCore::File::File):
>+        * html/DOMTokenList.cpp:
>+        (WebCore::DOMTokenList::toggle):
>+        * html/HTMLOListElement.h:
>+        * html/ImageBitmap.cpp:
>+        (WebCore::croppedSourceRectangleWithFormatting):
>+        * html/canvas/CanvasPattern.cpp:
>+        (WebCore::CanvasPattern::setTransform):
>+        * html/canvas/CanvasRenderingContext2DBase.cpp:
>+        (WebCore::CanvasRenderingContext2DBase::setTransform):
>+        (WebCore::CanvasRenderingContext2DBase::isPointInPathInternal):
>+        (WebCore::CanvasRenderingContext2DBase::isPointInStrokeInternal):
>+        * html/canvas/Path2D.cpp:
>+        (WebCore::Path2D::addPath):
>+        * inspector/InspectorCanvas.cpp:
>+        (WebCore::InspectorCanvas::buildAction):
>+        * inspector/InspectorFrontendHost.cpp:
>+        (WebCore::populateContextMenu):
>+        * layout/FormattingContext.cpp:
>+        (WebCore::Layout::FormattingContext::validateGeometryConstraintsAfterLayout const):
>+        * layout/FormattingContextGeometry.cpp:
>+        (WebCore::Layout::FormattingContext::Geometry::outOfFlowNonReplacedVerticalGeometry):
>+        (WebCore::Layout::FormattingContext::Geometry::outOfFlowNonReplacedHorizontalGeometry):
>+        (WebCore::Layout::FormattingContext::Geometry::outOfFlowReplacedVerticalGeometry):
>+        (WebCore::Layout::FormattingContext::Geometry::outOfFlowReplacedHorizontalGeometry):
>+        (WebCore::Layout::FormattingContext::Geometry::complicatedCases):
>+        (WebCore::Layout::FormattingContext::Geometry::inlineReplacedWidthAndMargin):
>+        (WebCore::Layout::FormattingContext::Geometry::inFlowPositionedPositionOffset):
>+        (WebCore::Layout::FormattingContext::Geometry::computedNonCollapsedHorizontalMarginValue):
>+        (WebCore::Layout::FormattingContext::Geometry::computedNonCollapsedVerticalMarginValue):
>+        * layout/FormattingContextQuirks.cpp:
>+        (WebCore::Layout::FormattingContext::Quirks::heightValueOfNearestContainingBlockWithFixedHeight):
>+        * layout/MarginTypes.h:
>+        (WebCore::Layout::VerticalMargin::usedValues const):
>+        * layout/blockformatting/BlockFormattingContextGeometry.cpp:
>+        (WebCore::Layout::BlockFormattingContext::Geometry::inFlowNonReplacedHeightAndMargin):
>+        (WebCore::Layout::BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin):
>+        (WebCore::Layout::BlockFormattingContext::Geometry::instrinsicWidthConstraints):
>+        * layout/blockformatting/BlockFormattingContextQuirks.cpp:
>+        (WebCore::Layout::BlockFormattingContext::Quirks::stretchedHeight):
>+        * layout/displaytree/DisplayBox.h:
>+        (WebCore::Display::Box::width const):
>+        (WebCore::Display::Box::height const):
>+        (WebCore::Display::Box::contentBoxTop const):
>+        (WebCore::Display::Box::contentBoxLeft const):
>+        * layout/floats/FloatingContext.cpp:
>+        (WebCore::Layout::Iterator::set):
>+        * layout/inlineformatting/InlineFormattingContext.cpp:
>+        (WebCore::Layout::InlineFormattingContext::appendContentToLine const):
>+        (WebCore::Layout::InlineFormattingContext::placeInFlowPositionedChildren const):
>+        * loader/FrameLoader.cpp:
>+        (WebCore::FrameLoader::urlSelected):
>+        * loader/NavigationAction.cpp:
>+        * page/FrameView.cpp:
>+        (WebCore::FrameView::setLayoutViewportOverrideRect):
>+        (WebCore::FrameView::documentToAbsoluteScaleFactor const):
>+        (WebCore::FrameView::viewportSizeForCSSViewportUnits const):
>+        * page/Page.cpp:
>+        (WebCore::Page::setLowPowerModeEnabledOverrideForTesting):
>+        * page/SecurityOriginData.cpp:
>+        (WebCore::SecurityOriginData::databaseIdentifier const):
>+        * page/SecurityOriginData.h:
>+        (WebCore::SecurityOriginDataHash::hash):
>+        * page/SecurityOriginHash.h:
>+        (WebCore::SecurityOriginHash::hash):
>+        * page/ViewportConfiguration.cpp:
>+        (WebCore::ViewportConfiguration::setViewLayoutSize):
>+        * page/WindowFeatures.cpp:
>+        (WebCore::parseDialogFeatures):
>+        * page/animation/AnimationBase.cpp:
>+        (WebCore::AnimationBase::updateStateMachine):
>+        (WebCore::AnimationBase::fireAnimationEventsIfNeeded):
>+        (WebCore::AnimationBase::getTimeToNextEvent const):
>+        (WebCore::AnimationBase::freezeAtTime):
>+        (WebCore::AnimationBase::getElapsedTime const):
>+        * page/animation/CSSAnimationController.cpp:
>+        (WebCore::CSSAnimationControllerPrivate::updateAnimationTimer):
>+        * page/cocoa/ResourceUsageThreadCocoa.mm:
>+        (WebCore::ResourceUsageThread::platformThreadBody):
>+        * page/linux/ResourceUsageThreadLinux.cpp:
>+        (WebCore::ResourceUsageThread::platformThreadBody):
>+        * platform/graphics/ComplexTextController.cpp:
>+        (WebCore::ComplexTextController::offsetForPosition):
>+        * platform/graphics/FontCache.h:
>+        (WebCore::FontDescriptionKey::computeHash const):
>+        * platform/graphics/FontCascade.cpp:
>+        (WebCore::FontCascade::drawText const):
>+        (WebCore::FontCascade::drawEmphasisMarks const):
>+        (WebCore::FontCascade::displayListForTextRun const):
>+        (WebCore::FontCascade::adjustSelectionRectForText const):
>+        (WebCore::FontCascade::codePath const):
>+        * platform/graphics/FontSelectionAlgorithm.cpp:
>+        (WebCore::FontSelectionAlgorithm::styleDistance const):
>+        * platform/graphics/FontSelectionAlgorithm.h:
>+        (WebCore::operator<<):
>+        (WebCore::FontSelectionSpecifiedCapabilities::computeWeight const):
>+        (WebCore::FontSelectionSpecifiedCapabilities::computeWidth const):
>+        (WebCore::FontSelectionSpecifiedCapabilities::computeSlope const):
>+        * platform/graphics/ShadowBlur.cpp:
>+        (WebCore::ShadowBlur::calculateLayerBoundingRect):
>+        * platform/graphics/avfoundation/cf/WebCoreAVCFResourceLoader.cpp:
>+        (WebCore::WebCoreAVCFResourceLoader::startLoading):
>+        * platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:
>+        (WebCore::MediaPlayerPrivateAVFoundationObjC::paintWithVideoOutput):
>+        * platform/graphics/avfoundation/objc/MediaPlayerPrivateMediaStreamAVFObjC.mm:
>+        (WebCore::MediaPlayerPrivateMediaStreamAVFObjC::paintCurrentFrameInContext):
>+        * platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm:
>+        (WebCore::SourceBufferPrivateAVFObjC::naturalSize):
>+        * platform/graphics/ca/GraphicsLayerCA.cpp:
>+        (WebCore::GraphicsLayerCA::setVisibleAndCoverageRects):
>+        * platform/graphics/cocoa/FontCacheCoreText.cpp:
>+        (WebCore::preparePlatformFont):
>+        * platform/graphics/filters/FETurbulence.cpp:
>+        (WebCore::FETurbulence::fillRegion const):
>+        * platform/graphics/gstreamer/GStreamerCommon.cpp:
>+        (WebCore::initializeGStreamer):
>+        * platform/graphics/texmap/TextureMapperLayer.cpp:
>+        (WebCore::TextureMapperLayer::paintSelfAndChildrenWithReplica):
>+        (WebCore::TextureMapperLayer::replicaTransform):
>+        (WebCore::TextureMapperLayer::syncAnimations):
>+        * platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp:
>+        (WebCore::CoordinatedGraphicsLayer::transformedVisibleRect):
>+        (WebCore::CoordinatedGraphicsLayer::computeTransformedVisibleRect):
>+        * platform/graphics/transforms/TransformState.cpp:
>+        (WebCore::TransformState::mappedPoint const):
>+        (WebCore::TransformState::mapQuad const):
>+        (WebCore::TransformState::flattenWithTransform):
>+        * platform/network/CacheValidation.cpp:
>+        (WebCore::computeCurrentAge):
>+        (WebCore::computeFreshnessLifetimeForHTTPFamily):
>+        * platform/network/NetworkStateNotifier.cpp:
>+        (WebCore::NetworkStateNotifier::onLine):
>+        * rendering/FloatingObjects.cpp:
>+        (WebCore::FindNextFloatLogicalBottomAdapter::nextLogicalBottom const):
>+        (WebCore::FindNextFloatLogicalBottomAdapter::nextShapeLogicalBottom const):
>+        * rendering/GridBaselineAlignment.cpp:
>+        (WebCore::GridBaselineAlignment::ascentForChild const):
>+        * rendering/GridTrackSizingAlgorithm.cpp:
>+        (WebCore::GridTrack::setGrowthLimit):
>+        (WebCore::GridTrackSizingAlgorithm::initialBaseSize const):
>+        (WebCore::GridTrackSizingAlgorithm::initialGrowthLimit const):
>+        (WebCore::GridTrackSizingAlgorithm::sizeTrackToFitNonSpanningItem):
>+        (WebCore::sortByGridTrackGrowthPotential):
>+        (WebCore::GridTrackSizingAlgorithm::estimatedGridAreaBreadthForChild const):
>+        (WebCore::GridTrackSizingAlgorithmStrategy::minSizeForChild const):
>+        (WebCore::GridTrackSizingAlgorithm::initializeTrackSizes):
>+        * rendering/PaintInfo.h:
>+        (WebCore::PaintInfo::applyTransform):
>+        * rendering/RenderBox.cpp:
>+        (WebCore::RenderBox::computeLogicalHeight const):
>+        * rendering/RenderCounter.cpp:
>+        (WebCore::planCounter):
>+        * rendering/RenderDeprecatedFlexibleBox.cpp:
>+        (WebCore::RenderDeprecatedFlexibleBox::layoutHorizontalBox):
>+        * rendering/RenderFlexibleBox.cpp:
>+        (WebCore::RenderFlexibleBox::baselinePosition const):
>+        (WebCore::RenderFlexibleBox::marginBoxAscentForChild):
>+        (WebCore::RenderFlexibleBox::adjustChildSizeForMinAndMax):
>+        * rendering/RenderGrid.cpp:
>+        (WebCore::RenderGrid::gridGap const):
>+        (WebCore::RenderGrid::baselinePosition const):
>+        * rendering/RenderLayer.cpp:
>+        (WebCore::RenderLayer::paintLayerByApplyingTransform):
>+        * rendering/RenderListBox.cpp:
>+        (WebCore::RenderListBox::paintItem):
>+        (WebCore::RenderListBox::listIndexIsVisible):
>+        * rendering/RenderMultiColumnSet.cpp:
>+        (WebCore::RenderMultiColumnSet::calculateMaxColumnHeight const):
>+        * rendering/RenderTable.cpp:
>+        (WebCore::RenderTable::convertStyleLogicalHeightToComputedHeight):
>+        * rendering/RenderTableCell.cpp:
>+        (WebCore::RenderTableCell::cellBaselinePosition const):
>+        * rendering/RenderTableSection.cpp:
>+        (WebCore::RenderTableSection::firstLineBaseline const):
>+        * rendering/RenderText.cpp:
>+        (WebCore::RenderText::computePreferredLogicalWidths):
>+        (WebCore::RenderText::previousOffset const):
>+        (WebCore::RenderText::previousOffsetForBackwardDeletion const):
>+        (WebCore::RenderText::nextOffset const):
>+        (WebCore::RenderText::stringView const):
>+        * rendering/RenderView.cpp:
>+        (WebCore::RenderView::layout):
>+        * rendering/mathml/RenderMathMLBlock.cpp:
>+        (WebCore::RenderMathMLBlock::baselinePosition const):
>+        * rendering/mathml/RenderMathMLBlock.h:
>+        (WebCore::RenderMathMLBlock::ascentForChild):
>+        * rendering/style/GridPosition.cpp:
>+        (WebCore::GridPosition::max):
>+        * rendering/style/TextUnderlineOffset.h:
>+        (WebCore::TextUnderlineOffset::lengthOr const):
>+        * rendering/svg/RenderSVGContainer.cpp:
>+        (WebCore::RenderSVGContainer::nodeAtFloatPoint):
>+        * rendering/svg/RenderSVGForeignObject.cpp:
>+        (WebCore::RenderSVGForeignObject::nodeAtFloatPoint):
>+        * rendering/svg/RenderSVGImage.cpp:
>+        (WebCore::RenderSVGImage::nodeAtFloatPoint):
>+        * rendering/svg/RenderSVGResourceClipper.cpp:
>+        (WebCore::RenderSVGResourceClipper::hitTestClipContent):
>+        * rendering/svg/RenderSVGResourceFilter.cpp:
>+        (WebCore::RenderSVGResourceFilter::postApplyResource):
>+        * rendering/svg/RenderSVGRoot.cpp:
>+        (WebCore::RenderSVGRoot::nodeAtPoint):
>+        * rendering/svg/RenderSVGShape.cpp:
>+        (WebCore::RenderSVGShape::nodeAtFloatPoint):
>+        * rendering/svg/RenderSVGText.cpp:
>+        (WebCore::RenderSVGText::nodeAtFloatPoint):
>+        * rendering/svg/SVGRenderingContext.cpp:
>+        (WebCore::SVGRenderingContext::clipToImageBuffer):
>+        * svg/SVGToOTFFontConversion.cpp:
>+        (WebCore::SVGToOTFFontConverter::processGlyphElement):
>+        (WebCore::SVGToOTFFontConverter::SVGToOTFFontConverter):
>+
> 2018-12-19  Michael Catanzaro  <mcatanzaro@igalia.com>
> 
>         Unreviewed, fix GTK build after r239410
>diff --git a/Source/WebDriver/ChangeLog b/Source/WebDriver/ChangeLog
>index 0f81c161a0773d9b5afb2d992c1364fe055a9885..27f525b7468fd369b736af18c74dd583efbba909 100644
>--- a/Source/WebDriver/ChangeLog
>+++ b/Source/WebDriver/ChangeLog
>@@ -1,3 +1,20 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * Session.cpp:
>+        (WebDriver::Session::handleUnexpectedAlertOpen):
>+        (WebDriver::Session::computeElementLayout):
>+        (WebDriver::Session::selectOptionElement):
>+        (WebDriver::builtAutomationCookie):
>+        (WebDriver::Session::takeScreenshot):
>+        * WebDriverService.cpp:
>+        (WebDriver::WebDriverService::sendResponse const):
>+        (WebDriver::WebDriverService::createSession):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
>index 3f27a965cc6c3e2d2729bdf506e629e5267a8825..a03f54b8143ab7543d101dac4803cf819f60ab44 100644
>--- a/Source/WebKit/ChangeLog
>+++ b/Source/WebKit/ChangeLog
>@@ -1,3 +1,53 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * Shared/API/c/WKSecurityOriginRef.cpp:
>+        (WKSecurityOriginGetPort):
>+        * UIProcess/API/APIProcessPoolConfiguration.h:
>+        * UIProcess/API/Cocoa/WKSecurityOrigin.mm:
>+        (-[WKSecurityOrigin port]):
>+        * UIProcess/API/Cocoa/WKWebViewConfiguration.mm:
>+        (-[WKWebViewConfiguration _cpuLimit]):
>+        * UIProcess/API/glib/WebKitSecurityOrigin.cpp:
>+        (webkit_security_origin_get_port):
>+        * UIProcess/API/gtk/WebKitWebViewBase.cpp:
>+        (webkitWebViewBaseHandleWheelEvent):
>+        * UIProcess/Automation/SimulatedInputDispatcher.cpp:
>+        (WebKit::SimulatedInputKeyFrame::maximumDuration const):
>+        (WebKit::SimulatedInputDispatcher::transitionInputSourceToState):
>+        * UIProcess/Automation/WebAutomationSession.cpp:
>+        (WebKit::WebAutomationSession::setWindowFrameOfBrowsingContext):
>+        (WebKit::WebAutomationSession::performInteractionSequence):
>+        * UIProcess/Automation/WebAutomationSessionMacros.h:
>+        * UIProcess/ServiceWorkerProcessProxy.cpp:
>+        (WebKit::ServiceWorkerProcessProxy::start):
>+        * UIProcess/WebAuthentication/AuthenticatorManager.cpp:
>+        (WebKit::AuthenticatorManager::initTimeOutTimer):
>+        * UIProcess/WebPageProxy.cpp:
>+        (WebKit::WebPageProxy::deviceScaleFactor const):
>+        * UIProcess/WebPageProxy.h:
>+        (WebKit::WebPageProxy::viewportSizeForCSSViewportUnits const):
>+        * UIProcess/gtk/WebPopupMenuProxyGtk.cpp:
>+        (WebKit::WebPopupMenuProxyGtk::activateItem):
>+        * UIProcess/mac/LegacySessionStateCoding.cpp:
>+        (WebKit::encodeFormDataElement):
>+        * WebProcess/Network/WebLoaderStrategy.cpp:
>+        (WebKit::WebLoaderStrategy::scheduleLoad):
>+        * WebProcess/Plugins/PDF/PDFPlugin.mm:
>+        (WebKit::PDFPlugin::convertFromPDFViewToRootView const):
>+        (WebKit::PDFPlugin::boundsOnScreen const):
>+        (WebKit::PDFPlugin::geometryDidChange):
>+        * WebProcess/WebCoreSupport/SessionStateConversion.cpp:
>+        (WebKit::toFormData):
>+        * WebProcess/WebPage/ios/WebPageIOS.mm:
>+        (WebKit::WebPage::updateVisibleContentRects):
>+        * WebProcess/WebPage/wpe/CompositingManager.cpp:
>+        (WebKit::CompositingManager::releaseConnectionFd):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/WebKitLegacy/mac/ChangeLog b/Source/WebKitLegacy/mac/ChangeLog
>index eb1d1100885843d02f4461b82175c51260da5a98..6f50b277dd3877fe5b2679b9aece9baa085a6ba5 100644
>--- a/Source/WebKitLegacy/mac/ChangeLog
>+++ b/Source/WebKitLegacy/mac/ChangeLog
>@@ -1,3 +1,13 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * WebCoreSupport/WebSecurityOrigin.mm:
>+        (-[WebSecurityOrigin port]):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/WebKitLegacy/win/ChangeLog b/Source/WebKitLegacy/win/ChangeLog
>index f6c126b72137339727b26f339f098b273fbefcd7..5b6a299355fe746dc457816555c320b89d6b1a26 100644
>--- a/Source/WebKitLegacy/win/ChangeLog
>+++ b/Source/WebKitLegacy/win/ChangeLog
>@@ -1,3 +1,13 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * WebSecurityOrigin.cpp:
>+        (WebSecurityOrigin::port):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>index 87215c33ae5923c15a5cd4de6f2c389fb22b1548..2fafa1211bcfdd47c1f60401a6a33336d3ac8c37 100644
>--- a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>+++ b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>@@ -159,7 +159,7 @@ bool RemoteConnectionToTarget::setup(bool isAutomaticInspection, bool automatica
>     if (!m_target)
>         return false;
> 
>-    unsigned targetIdentifier = this->targetIdentifier().value_or(0);
>+    unsigned targetIdentifier = this->targetIdentifier().valueOr(0);
>     
>     ref();
>     dispatchAsyncOnTarget(^{
>diff --git a/Source/JavaScriptCore/inspector/remote/glib/RemoteConnectionToTargetGlib.cpp b/Source/JavaScriptCore/inspector/remote/glib/RemoteConnectionToTargetGlib.cpp
>index 3b5c681555a0bfff203f697e498522820ad9fe5d..5dde88809b2541f332a205dec0addf5ee503cc42 100644
>--- a/Source/JavaScriptCore/inspector/remote/glib/RemoteConnectionToTargetGlib.cpp
>+++ b/Source/JavaScriptCore/inspector/remote/glib/RemoteConnectionToTargetGlib.cpp
>@@ -49,7 +49,7 @@ bool RemoteConnectionToTarget::setup(bool isAutomaticInspection, bool automatica
>     if (!m_target)
>         return false;
> 
>-    unsigned targetIdentifier = this->targetIdentifier().value_or(0);
>+    unsigned targetIdentifier = this->targetIdentifier().valueOr(0);
> 
>     if (!m_target || !m_target->remoteControlAllowed()) {
>         RemoteInspector::singleton().setupFailed(targetIdentifier);
>diff --git a/Source/JavaScriptCore/parser/SourceCodeKey.h b/Source/JavaScriptCore/parser/SourceCodeKey.h
>index 2b03aa50287305032e1b2e4a0d0658699b5752b5..a8e603c26a0b60362a02deac0516169d57558021 100644
>--- a/Source/JavaScriptCore/parser/SourceCodeKey.h
>+++ b/Source/JavaScriptCore/parser/SourceCodeKey.h
>@@ -82,7 +82,7 @@ public:
>             : m_sourceCode(sourceCode)
>             , m_name(name)
>             , m_flags(codeType, strictMode, scriptMode, derivedContextType, evalContextType, isArrowFunctionContext, debuggerMode, typeProfilerEnabled, controlFlowProfilerEnabled)
>-            , m_functionConstructorParametersEndPosition(functionConstructorParametersEndPosition.value_or(-1))
>+            , m_functionConstructorParametersEndPosition(functionConstructorParametersEndPosition.valueOr(-1))
>             , m_hash(sourceCode.hash() ^ m_flags.bits())
>     {
>     }
>diff --git a/Source/JavaScriptCore/wasm/js/WebAssemblyModuleRecord.cpp b/Source/JavaScriptCore/wasm/js/WebAssemblyModuleRecord.cpp
>index c5708bcba4a58a0803f6429c2f7583c9db27257c..2dc0ae71fae37d2fb1a2516ae6bccb9bf079734e 100644
>--- a/Source/JavaScriptCore/wasm/js/WebAssemblyModuleRecord.cpp
>+++ b/Source/JavaScriptCore/wasm/js/WebAssemblyModuleRecord.cpp
>@@ -412,7 +412,7 @@ void WebAssemblyModuleRecord::link(ExecState* exec, JSValue, JSObject* importObj
> 
>     bool hasStart = !!moduleInformation.startFunctionIndexSpace;
>     if (hasStart) {
>-        auto startFunctionIndexSpace = moduleInformation.startFunctionIndexSpace.value_or(0);
>+        auto startFunctionIndexSpace = moduleInformation.startFunctionIndexSpace.valueOr(0);
>         Wasm::SignatureIndex signatureIndex = module->signatureIndexFromFunctionIndexSpace(startFunctionIndexSpace);
>         const Wasm::Signature& signature = Wasm::SignatureInformation::get(signatureIndex);
>         // The start function must not take any arguments or return anything. This is enforced by the parser.
>diff --git a/Source/WTF/wtf/Optional.h b/Source/WTF/wtf/Optional.h
>index a605be01946a0ec9b0f5219fb0f0d0652f03fbba..6d4e2426b745d927b5b4e66dd55ba3c68dbd4786 100644
>--- a/Source/WTF/wtf/Optional.h
>+++ b/Source/WTF/wtf/Optional.h
>@@ -557,26 +557,12 @@ public:
>     return *this ? **this : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>   }
> 
>-  // FIXME: Remove this.
>-  template <class V>
>-  constexpr T value_or(V&& v) const&
>-  {
>-    return *this ? **this : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>-  }
>-
>   template <class V>
>   OPTIONAL_MUTABLE_CONSTEXPR T valueOr(V&& v) &&
>   {
>     return *this ? detail_::constexpr_move(const_cast<Optional<T>&>(*this).contained_val()) : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>   }
> 
>-  // FIXME: Remove this.
>-  template <class V>
>-  OPTIONAL_MUTABLE_CONSTEXPR T value_or(V&& v) &&
>-  {
>-    return *this ? detail_::constexpr_move(const_cast<Optional<T>&>(*this).contained_val()) : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>-  }
>-
> # else
> 
>   template <class V>
>@@ -585,13 +571,6 @@ public:
>     return *this ? **this : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>   }
> 
>-  // FIXME: Remove this.
>-  template <class V>
>-  constexpr T value_or(V&& v) const
>-  {
>-    return *this ? **this : detail_::convert<T>(detail_::constexpr_forward<V>(v));
>-  }
>-
> # endif
> 
>   // 20.6.3.6, modifiers
>@@ -699,7 +678,7 @@ public:
>   }
> 
>   template <class V>
>-  constexpr typename std::decay<T>::type value_or(V&& v) const
>+  constexpr typename std::decay<T>::type valueOr(V&& v) const
>   {
>     return *this ? **this : detail_::convert<typename std::decay<T>::type>(detail_::constexpr_forward<V>(v));
>   }
>diff --git a/Source/WebCore/Modules/applepay/paymentrequest/ApplePayPaymentHandler.cpp b/Source/WebCore/Modules/applepay/paymentrequest/ApplePayPaymentHandler.cpp
>index 156d08602c44d93b55efc5feaa7e492c64098f1a..ea44d5f8e14987467d6f2e912847bc185ed70042 100644
>--- a/Source/WebCore/Modules/applepay/paymentrequest/ApplePayPaymentHandler.cpp
>+++ b/Source/WebCore/Modules/applepay/paymentrequest/ApplePayPaymentHandler.cpp
>@@ -547,7 +547,7 @@ void ApplePayPaymentHandler::validateMerchant(URL&& validationURL)
> 
> static Ref<PaymentAddress> convert(const ApplePayPaymentContact& contact)
> {
>-    return PaymentAddress::create(contact.countryCode, contact.addressLines.value_or(Vector<String>()), contact.administrativeArea, contact.locality, contact.subLocality, contact.postalCode, String(), String(), contact.localizedName, contact.phoneNumber);
>+    return PaymentAddress::create(contact.countryCode, contact.addressLines.valueOr(Vector<String>()), contact.administrativeArea, contact.locality, contact.subLocality, contact.postalCode, String(), String(), contact.localizedName, contact.phoneNumber);
> }
> 
> template<typename T>
>@@ -562,7 +562,7 @@ void ApplePayPaymentHandler::didAuthorizePayment(const Payment& payment)
>     ASSERT(!m_isUpdating);
> 
>     auto applePayPayment = payment.toApplePayPayment(version());
>-    auto shippingContact = applePayPayment.shippingContact.value_or(ApplePayPaymentContact());
>+    auto shippingContact = applePayPayment.shippingContact.valueOr(ApplePayPaymentContact());
>     auto detailsFunction = [applePayPayment = WTFMove(applePayPayment)](JSC::ExecState& execState) {
>         return toJSDictionary(execState, applePayPayment);
>     };
>diff --git a/Source/WebCore/Modules/encryptedmedia/MediaKeySession.cpp b/Source/WebCore/Modules/encryptedmedia/MediaKeySession.cpp
>index 392a37c636a8563a865800605fb09b2908df552a..4bea9a0084bee6873298dd34bea37a04eaa69fda 100644
>--- a/Source/WebCore/Modules/encryptedmedia/MediaKeySession.cpp
>+++ b/Source/WebCore/Modules/encryptedmedia/MediaKeySession.cpp
>@@ -342,7 +342,7 @@ void MediaKeySession::load(const String& sessionId, Ref<DeferredPromise>&& promi
> 
>                 // 8.9.5. Run the Update Expiration algorithm on the session, providing expiration time.
>                 // This must be run, and NaN is the default value if the CDM instance doesn't provide one.
>-                updateExpiration(expiration.value_or(std::numeric_limits<double>::quiet_NaN()));
>+                updateExpiration(expiration.valueOr(std::numeric_limits<double>::quiet_NaN()));
> 
>                 // 8.9.6. If message is not null, run the Queue a "message" Event algorithm on the session, providing message type and message.
>                 if (message)
>diff --git a/Source/WebCore/Modules/indexeddb/IDBDatabaseIdentifier.h b/Source/WebCore/Modules/indexeddb/IDBDatabaseIdentifier.h
>index f42a9f9d8014d871d73eb9588190cc0bbb8b7c13..e6eb4bf071b1f64bbdd6adaf11f5df47b6e0b586 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBDatabaseIdentifier.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBDatabaseIdentifier.h
>@@ -62,7 +62,7 @@ public:
>         unsigned mainFrameProtocolHash = StringHash::hash(m_mainFrameOrigin.protocol);
>         unsigned mainFrameHostHash = StringHash::hash(m_mainFrameOrigin.host);
>         
>-        unsigned hashCodes[8] = { nameHash, sessionIDHash, openingProtocolHash, openingHostHash, m_openingOrigin.port.value_or(0), mainFrameProtocolHash, mainFrameHostHash, m_mainFrameOrigin.port.value_or(0) };
>+        unsigned hashCodes[8] = { nameHash, sessionIDHash, openingProtocolHash, openingHostHash, m_openingOrigin.port.valueOr(0), mainFrameProtocolHash, mainFrameHostHash, m_mainFrameOrigin.port.valueOr(0) };
>         return StringHasher::hashMemory<sizeof(hashCodes)>(hashCodes);
>     }
> 
>diff --git a/Source/WebCore/Modules/indexeddb/IDBFactory.cpp b/Source/WebCore/Modules/indexeddb/IDBFactory.cpp
>index 974c53479a933776ae1ff9b5afcbac71c308fafe..ea1f84976478c28747d767e5b4c7cc6b5121f037 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBFactory.cpp
>+++ b/Source/WebCore/Modules/indexeddb/IDBFactory.cpp
>@@ -79,7 +79,7 @@ ExceptionOr<Ref<IDBOpenDBRequest>> IDBFactory::open(ScriptExecutionContext& cont
>     if (version && !version.value())
>         return Exception { TypeError, "IDBFactory.open() called with a version of 0"_s };
> 
>-    return openInternal(context, name, version.value_or(0));
>+    return openInternal(context, name, version.valueOr(0));
> }
> 
> ExceptionOr<Ref<IDBOpenDBRequest>> IDBFactory::openInternal(ScriptExecutionContext& context, const String& name, uint64_t version)
>diff --git a/Source/WebCore/Modules/mediastream/MediaStreamTrack.cpp b/Source/WebCore/Modules/mediastream/MediaStreamTrack.cpp
>index b5937c729444e091e6f7727029936834b608cf16..6a7f146ca1c4d7e515a154851df9bd37a053d183 100644
>--- a/Source/WebCore/Modules/mediastream/MediaStreamTrack.cpp
>+++ b/Source/WebCore/Modules/mediastream/MediaStreamTrack.cpp
>@@ -340,7 +340,7 @@ void MediaStreamTrack::applyConstraints(const Optional<MediaTrackConstraints>& c
>         if (!weakThis || !weakThis->m_promise)
>             return;
>         weakThis->m_promise->resolve();
>-        weakThis->m_constraints = constraints.value_or(MediaTrackConstraints { });
>+        weakThis->m_constraints = constraints.valueOr(MediaTrackConstraints { });
>     };
>     m_private->applyConstraints(createMediaConstraints(constraints), WTFMove(successHandler), WTFMove(failureHandler));
> }
>diff --git a/Source/WebCore/Modules/mediastream/RTCDTMFSender.cpp b/Source/WebCore/Modules/mediastream/RTCDTMFSender.cpp
>index 3f26e65e5872cbcad9bd2830694c97df8b36fa54..53ddc12a2397a0d162831578b34d1a7218037669 100644
>--- a/Source/WebCore/Modules/mediastream/RTCDTMFSender.cpp
>+++ b/Source/WebCore/Modules/mediastream/RTCDTMFSender.cpp
>@@ -79,8 +79,8 @@ ExceptionOr<void> RTCDTMFSender::insertDTMF(const String&, Optional<int> duratio
>     if (interToneGap && interToneGap.value() < minInterToneGapMs)
>         return Exception { SyntaxError };
> 
>-    m_duration = duration.value_or(defaultToneDurationMs);
>-    m_interToneGap = interToneGap.value_or(defaultInterToneGapMs);
>+    m_duration = duration.valueOr(defaultToneDurationMs);
>+    m_interToneGap = interToneGap.valueOr(defaultInterToneGapMs);
> 
>     return Exception { SyntaxError };
> }
>diff --git a/Source/WebCore/Modules/webdatabase/SQLTransaction.cpp b/Source/WebCore/Modules/webdatabase/SQLTransaction.cpp
>index 197798067dbbd8d4d97dfc85eb1650d523c837ec..5091c8341adcd91aa020197a4a9c846b2edacb6d 100644
>--- a/Source/WebCore/Modules/webdatabase/SQLTransaction.cpp
>+++ b/Source/WebCore/Modules/webdatabase/SQLTransaction.cpp
>@@ -81,7 +81,7 @@ ExceptionOr<void> SQLTransaction::executeSql(const String& sqlStatement, Optiona
>     else if (m_readOnly)
>         permissions |= DatabaseAuthorizer::ReadOnlyMask;
> 
>-    auto statement = std::make_unique<SQLStatement>(m_database, sqlStatement, arguments.value_or(Vector<SQLValue> { }), WTFMove(callback), WTFMove(callbackError), permissions);
>+    auto statement = std::make_unique<SQLStatement>(m_database, sqlStatement, arguments.valueOr(Vector<SQLValue> { }), WTFMove(callback), WTFMove(callbackError), permissions);
> 
>     if (m_database->deleted())
>         statement->setDatabaseDeletedError();
>diff --git a/Source/WebCore/Modules/webvr/VRFrameData.cpp b/Source/WebCore/Modules/webvr/VRFrameData.cpp
>index b215b55fc6c031b07d69c72d5fa0d9e5eba71c0c..a7c7db9d63007f1b043ffa37bc578cfb74ad3b2d 100644
>--- a/Source/WebCore/Modules/webvr/VRFrameData.cpp
>+++ b/Source/WebCore/Modules/webvr/VRFrameData.cpp
>@@ -128,8 +128,8 @@ void VRFrameData::update(const VRPlatformTrackingInfo& trackingInfo, const VREye
>     m_timestamp = trackingInfo.timestamp;
>     m_pose->update(trackingInfo);
> 
>-    auto rotationMatrix = rotationMatrixFromQuaternion(trackingInfo.orientation.value_or(VRPlatformTrackingInfo::Quaternion(0, 0, 0, 1)));
>-    FloatPoint3D position = trackingInfo.position.value_or(FloatPoint3D(0, 0, 0));
>+    auto rotationMatrix = rotationMatrixFromQuaternion(trackingInfo.orientation.valueOr(VRPlatformTrackingInfo::Quaternion(0, 0, 0, 1)));
>+    FloatPoint3D position = trackingInfo.position.valueOr(FloatPoint3D(0, 0, 0));
>     rotationMatrix.translate3d(-position.x(), -position.y(), -position.z());
> 
>     m_leftViewMatrix = rotationMatrix;
>diff --git a/Source/WebCore/animation/AnimationTimeline.cpp b/Source/WebCore/animation/AnimationTimeline.cpp
>index fcba25cbec5f01e5d7c4c0bdcd527de92a6469ad..625d4f0f5740599f42cbfca32f70343879f90ef6 100644
>--- a/Source/WebCore/animation/AnimationTimeline.cpp
>+++ b/Source/WebCore/animation/AnimationTimeline.cpp
>@@ -460,7 +460,7 @@ void AnimationTimeline::updateCSSTransitionsForElement(Element& element, const R
>                 auto& reversingAdjustedStartStyle = previouslyRunningTransition->targetStyle();
>                 double transformedProgress = 1;
>                 if (auto* effect = previouslyRunningTransition->effect())
>-                    transformedProgress = effect->iterationProgress().value_or(transformedProgress);
>+                    transformedProgress = effect->iterationProgress().valueOr(transformedProgress);
>                 auto reversingShorteningFactor = std::max(std::min(((transformedProgress * previouslyRunningTransition->reversingShorteningFactor()) + (1 - previouslyRunningTransition->reversingShorteningFactor())), 1.0), 0.0);
>                 auto delay = matchingBackingAnimation->delay() < 0 ? Seconds(matchingBackingAnimation->delay()) * reversingShorteningFactor : Seconds(matchingBackingAnimation->delay());
>                 auto duration = Seconds(matchingBackingAnimation->duration()) * reversingShorteningFactor;
>diff --git a/Source/WebCore/animation/DeclarativeAnimation.cpp b/Source/WebCore/animation/DeclarativeAnimation.cpp
>index 0c20c5287cb53a20e90a3a8b322e4d21226e7e88..76c83b42e4289673daa9400db49ce48602611de3 100644
>--- a/Source/WebCore/animation/DeclarativeAnimation.cpp
>+++ b/Source/WebCore/animation/DeclarativeAnimation.cpp
>@@ -199,7 +199,7 @@ void DeclarativeAnimation::cancel()
> {
>     auto cancelationTime = 0_s;
>     if (auto animationEffect = effect())
>-        cancelationTime = animationEffect->activeTime().value_or(0_s);
>+        cancelationTime = animationEffect->activeTime().valueOr(0_s);
> 
>     WebAnimation::cancel();
> 
>@@ -236,7 +236,7 @@ void DeclarativeAnimation::invalidateDOMEvents(Seconds elapsedTime)
>     if (isPending && m_wasPending)
>         return;
> 
>-    auto iteration = animationEffect ? animationEffect->currentIteration().value_or(0) : 0;
>+    auto iteration = animationEffect ? animationEffect->currentIteration().valueOr(0) : 0;
>     auto currentPhase = animationEffect ? animationEffect->phase() : phaseWithoutEffect();
> 
>     bool wasActive = m_previousPhase == AnimationEffect::Phase::Active;
>diff --git a/Source/WebCore/animation/KeyframeEffect.cpp b/Source/WebCore/animation/KeyframeEffect.cpp
>index 1e6462d3b8a29db1979bbcc5d563d2c176eb0c88..13dbcd0fd133979c92351cfb0460d98211a730c3 100644
>--- a/Source/WebCore/animation/KeyframeEffect.cpp
>+++ b/Source/WebCore/animation/KeyframeEffect.cpp
>@@ -116,7 +116,7 @@ static inline void computeMissingKeyframeOffsets(Vector<KeyframeEffect::ParsedKe
>     // that a keyframe hasn't had a computed offset by checking if it has a null offset and a 0 computedOffset, since the first
>     // keyframe will already have a 0 computedOffset.
>     for (auto& keyframe : keyframes)
>-        keyframe.computedOffset = keyframe.offset.value_or(0);
>+        keyframe.computedOffset = keyframe.offset.valueOr(0);
> 
>     // 2. If keyframes contains more than one keyframe and the computed keyframe offset of the first keyframe in keyframes is null,
>     //    set the computed keyframe offset of the first keyframe to 0.
>@@ -1314,7 +1314,7 @@ void KeyframeEffect::applyPendingAcceleratedActions()
>     auto* compositedRenderer = downcast<RenderBoxModelObject>(renderer);
> 
>     // To simplify the code we use a default of 0s for an unresolved current time since for a Stop action that is acceptable.
>-    auto timeOffset = animation()->currentTime().value_or(0_s).seconds() - delay().seconds();
>+    auto timeOffset = animation()->currentTime().valueOr(0_s).seconds() - delay().seconds();
> 
>     for (const auto& action : pendingAcceleratedActions) {
>         switch (action) {
>diff --git a/Source/WebCore/animation/WebAnimation.cpp b/Source/WebCore/animation/WebAnimation.cpp
>index 67e9812df41d11a7f2ba3438ef5f7e800db1b2cb..338cca3da3ccca4cf8456953c468bba64898bd48 100644
>--- a/Source/WebCore/animation/WebAnimation.cpp
>+++ b/Source/WebCore/animation/WebAnimation.cpp
>@@ -917,7 +917,7 @@ void WebAnimation::runPendingPlayTask()
>         // Subsequently, the resulting readyTime value can be null. Unify behavior between C++17 and
>         // C++14 builds (the latter using WTF's Optional) and avoid null Optional dereferencing
>         // by defaulting to a Seconds(0) value. See https://bugs.webkit.org/show_bug.cgi?id=186189.
>-        auto newStartTime = readyTime.value_or(0_s);
>+        auto newStartTime = readyTime.valueOr(0_s);
>         if (m_playbackRate)
>             newStartTime -= m_holdTime.value() / m_playbackRate;
>         // 3. Set the start time of animation to new start time.
>@@ -928,7 +928,7 @@ void WebAnimation::runPendingPlayTask()
>     } else if (m_startTime && m_pendingPlaybackRate) {
>         // If animation's start time is resolved and animation has a pending playback rate,
>         // 1. Let current time to match be the result of evaluating (ready time - start time) Ã playback rate for animation.
>-        auto currentTimeToMatch = (readyTime.value_or(0_s) - m_startTime.value()) * m_playbackRate;
>+        auto currentTimeToMatch = (readyTime.valueOr(0_s) - m_startTime.value()) * m_playbackRate;
>         // 2. Apply any pending playback rate on animation.
>         applyPendingPlaybackRate();
>         // 3. If animation's playback rate is zero, let animation's hold time be current time to match.
>@@ -936,7 +936,7 @@ void WebAnimation::runPendingPlayTask()
>             m_holdTime = currentTimeToMatch;
>         // 4. Let new start time be the result of evaluating ready time - current time to match / playback rate for animation.
>         // If the playback rate is zero, let new start time be simply ready time.
>-        auto newStartTime = readyTime.value_or(0_s);
>+        auto newStartTime = readyTime.valueOr(0_s);
>         if (m_playbackRate)
>             newStartTime -= currentTimeToMatch / m_playbackRate;
>         // 5. Set the start time of animation to new start time.
>@@ -1059,7 +1059,7 @@ void WebAnimation::runPendingPauseTask()
>         // Subsequently, the resulting readyTime value can be null. Unify behavior between C++17 and
>         // C++14 builds (the latter using WTF's Optional) and avoid null Optional dereferencing
>         // by defaulting to a Seconds(0) value. See https://bugs.webkit.org/show_bug.cgi?id=186189.
>-        m_holdTime = (readyTime.value_or(0_s) - animationStartTime.value()) * m_playbackRate;
>+        m_holdTime = (readyTime.valueOr(0_s) - animationStartTime.value()) * m_playbackRate;
>     }
> 
>     // 3. Apply any pending playback rate on animation.
>diff --git a/Source/WebCore/bindings/js/SerializedScriptValue.cpp b/Source/WebCore/bindings/js/SerializedScriptValue.cpp
>index 99981085b5505c745c975a6d97abc58ceae1c5f9..72ff7ca5c94b502af37196722b8dc33159495c2f 100644
>--- a/Source/WebCore/bindings/js/SerializedScriptValue.cpp
>+++ b/Source/WebCore/bindings/js/SerializedScriptValue.cpp
>@@ -1262,7 +1262,7 @@ private:
>         write(file.url());
>         write(file.type());
>         write(file.name());
>-        write(static_cast<double>(file.lastModifiedOverride().value_or(-1)));
>+        write(static_cast<double>(file.lastModifiedOverride().valueOr(-1)));
>     }
> 
> #if ENABLE(WEB_CRYPTO)
>diff --git a/Source/WebCore/crypto/algorithms/CryptoAlgorithmHMAC.cpp b/Source/WebCore/crypto/algorithms/CryptoAlgorithmHMAC.cpp
>index 02b21711e7fbe4bff24ad28160e35316a6fd71f2..4bfb4efb8e057ab6d97da211cb8c7a997b9649cd 100644
>--- a/Source/WebCore/crypto/algorithms/CryptoAlgorithmHMAC.cpp
>+++ b/Source/WebCore/crypto/algorithms/CryptoAlgorithmHMAC.cpp
>@@ -87,7 +87,7 @@ void CryptoAlgorithmHMAC::generateKey(const CryptoAlgorithmParameters& parameter
>         return;
>     }
> 
>-    auto result = CryptoKeyHMAC::generate(hmacParameters.length.value_or(0), hmacParameters.hashIdentifier, extractable, usages);
>+    auto result = CryptoKeyHMAC::generate(hmacParameters.length.valueOr(0), hmacParameters.hashIdentifier, extractable, usages);
>     if (!result) {
>         exceptionCallback(OperationError);
>         return;
>@@ -110,7 +110,7 @@ void CryptoAlgorithmHMAC::importKey(CryptoKeyFormat format, KeyData&& data, cons
>     RefPtr<CryptoKeyHMAC> result;
>     switch (format) {
>     case CryptoKeyFormat::Raw:
>-        result = CryptoKeyHMAC::importRaw(hmacParameters.length.value_or(0), hmacParameters.hashIdentifier, WTFMove(WTF::get<Vector<uint8_t>>(data)), extractable, usages);
>+        result = CryptoKeyHMAC::importRaw(hmacParameters.length.valueOr(0), hmacParameters.hashIdentifier, WTFMove(WTF::get<Vector<uint8_t>>(data)), extractable, usages);
>         break;
>     case CryptoKeyFormat::Jwk: {
>         auto checkAlgCallback = [](CryptoAlgorithmIdentifier hash, const String& alg) -> bool {
>@@ -130,7 +130,7 @@ void CryptoAlgorithmHMAC::importKey(CryptoKeyFormat format, KeyData&& data, cons
>             }
>             return false;
>         };
>-        result = CryptoKeyHMAC::importJwk(hmacParameters.length.value_or(0), hmacParameters.hashIdentifier, WTFMove(WTF::get<JsonWebKey>(data)), extractable, usages, WTFMove(checkAlgCallback));
>+        result = CryptoKeyHMAC::importJwk(hmacParameters.length.valueOr(0), hmacParameters.hashIdentifier, WTFMove(WTF::get<JsonWebKey>(data)), extractable, usages, WTFMove(checkAlgCallback));
>         break;
>     }
>     default:
>diff --git a/Source/WebCore/crypto/gcrypt/CryptoAlgorithmAES_GCMGCrypt.cpp b/Source/WebCore/crypto/gcrypt/CryptoAlgorithmAES_GCMGCrypt.cpp
>index 3ccc1e6dc508650f26755aa07dad16fa856efd2a..ffbc93c91e95bc09a0dce57ad7de5159a46e6dc9 100644
>--- a/Source/WebCore/crypto/gcrypt/CryptoAlgorithmAES_GCMGCrypt.cpp
>+++ b/Source/WebCore/crypto/gcrypt/CryptoAlgorithmAES_GCMGCrypt.cpp
>@@ -181,7 +181,7 @@ static Optional<Vector<uint8_t>> gcryptDecrypt(const Vector<uint8_t>& key, const
> 
> ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_GCM::platformEncrypt(const CryptoAlgorithmAesGcmParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& plainText)
> {
>-    auto output = gcryptEncrypt(key.key(), parameters.ivVector(), plainText, parameters.additionalDataVector(), parameters.tagLength.value_or(0) / 8);
>+    auto output = gcryptEncrypt(key.key(), parameters.ivVector(), plainText, parameters.additionalDataVector(), parameters.tagLength.valueOr(0) / 8);
>     if (!output)
>         return Exception { OperationError };
>     return WTFMove(*output);
>@@ -189,7 +189,7 @@ ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_GCM::platformEncrypt(const Crypt
> 
> ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_GCM::platformDecrypt(const CryptoAlgorithmAesGcmParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& cipherText)
> {
>-    auto output = gcryptDecrypt(key.key(), parameters.ivVector(), cipherText, parameters.additionalDataVector(), parameters.tagLength.value_or(0) / 8);
>+    auto output = gcryptDecrypt(key.key(), parameters.ivVector(), cipherText, parameters.additionalDataVector(), parameters.tagLength.valueOr(0) / 8);
>     if (!output)
>         return Exception { OperationError };
>     return WTFMove(*output);
>diff --git a/Source/WebCore/crypto/gcrypt/CryptoKeyRSAGCrypt.cpp b/Source/WebCore/crypto/gcrypt/CryptoKeyRSAGCrypt.cpp
>index c642ca68f3fefe1655f79b4ba584ec3077c5fb26..dfc5ba4d9be0dfe9da2254fe285583351d925400 100644
>--- a/Source/WebCore/crypto/gcrypt/CryptoKeyRSAGCrypt.cpp
>+++ b/Source/WebCore/crypto/gcrypt/CryptoKeyRSAGCrypt.cpp
>@@ -313,7 +313,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importSpki(CryptoAlgorithmIdentifier identifi
>         }
>     }
> 
>-    return adoptRef(new CryptoKeyRSA(identifier, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Public, platformKey.release(), extractable, usages));
>+    return adoptRef(new CryptoKeyRSA(identifier, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Public, platformKey.release(), extractable, usages));
> }
> 
> RefPtr<CryptoKeyRSA> CryptoKeyRSA::importPkcs8(CryptoAlgorithmIdentifier identifier, Optional<CryptoAlgorithmIdentifier> hash, Vector<uint8_t>&& keyData, bool extractable, CryptoKeyUsageBitmap usages)
>@@ -408,7 +408,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importPkcs8(CryptoAlgorithmIdentifier identif
>         }
>     }
> 
>-    return adoptRef(new CryptoKeyRSA(identifier, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Private, platformKey.release(), extractable, usages));
>+    return adoptRef(new CryptoKeyRSA(identifier, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Private, platformKey.release(), extractable, usages));
> }
> 
> ExceptionOr<Vector<uint8_t>> CryptoKeyRSA::exportSpki() const
>diff --git a/Source/WebCore/crypto/keys/CryptoKeyRSA.cpp b/Source/WebCore/crypto/keys/CryptoKeyRSA.cpp
>index 73de51aeb214e164e17fd50af80f438dfb39bbfa..ec06773c449a744776ff6372bfa314ab2cb70cb6 100644
>--- a/Source/WebCore/crypto/keys/CryptoKeyRSA.cpp
>+++ b/Source/WebCore/crypto/keys/CryptoKeyRSA.cpp
>@@ -58,7 +58,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importJwk(CryptoAlgorithmIdentifier algorithm
>         // import public key
>         auto publicKeyComponents = CryptoKeyRSAComponents::createPublic(WTFMove(modulus), WTFMove(exponent));
>         // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-        return CryptoKeyRSA::create(algorithm, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, *publicKeyComponents, extractable, usages);
>+        return CryptoKeyRSA::create(algorithm, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, *publicKeyComponents, extractable, usages);
>     }
> 
>     // import private key
>@@ -68,7 +68,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importJwk(CryptoAlgorithmIdentifier algorithm
>     if (keyData.p.isNull() && keyData.q.isNull() && keyData.dp.isNull() && keyData.dp.isNull() && keyData.qi.isNull()) {
>         auto privateKeyComponents = CryptoKeyRSAComponents::createPrivate(WTFMove(modulus), WTFMove(exponent), WTFMove(privateExponent));
>         // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-        return CryptoKeyRSA::create(algorithm, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
>+        return CryptoKeyRSA::create(algorithm, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
>     }
> 
>     if (keyData.p.isNull() || keyData.q.isNull() || keyData.dp.isNull() || keyData.dq.isNull() || keyData.qi.isNull())
>@@ -88,7 +88,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importJwk(CryptoAlgorithmIdentifier algorithm
>     if (!keyData.oth) {
>         auto privateKeyComponents = CryptoKeyRSAComponents::createPrivateWithAdditionalData(WTFMove(modulus), WTFMove(exponent), WTFMove(privateExponent), WTFMove(firstPrimeInfo), WTFMove(secondPrimeInfo), { });
>         // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-        return CryptoKeyRSA::create(algorithm, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
>+        return CryptoKeyRSA::create(algorithm, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
>     }
> 
>     Vector<CryptoKeyRSAComponents::PrimeInfo> otherPrimeInfos;
>@@ -105,7 +105,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importJwk(CryptoAlgorithmIdentifier algorithm
> 
>     auto privateKeyComponents = CryptoKeyRSAComponents::createPrivateWithAdditionalData(WTFMove(modulus), WTFMove(exponent), WTFMove(privateExponent), WTFMove(firstPrimeInfo), WTFMove(secondPrimeInfo), WTFMove(otherPrimeInfos));
>     // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-    return CryptoKeyRSA::create(algorithm, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
>+    return CryptoKeyRSA::create(algorithm, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, *privateKeyComponents, extractable, usages);
> }
> 
> JsonWebKey CryptoKeyRSA::exportJwk() const
>diff --git a/Source/WebCore/crypto/mac/CryptoAlgorithmAES_GCMMac.cpp b/Source/WebCore/crypto/mac/CryptoAlgorithmAES_GCMMac.cpp
>index e268ff5eec97737b779c4eb1c1ad30ddb996d997..923441518e7b99a7a87cb8317052c78540e0abe4 100644
>--- a/Source/WebCore/crypto/mac/CryptoAlgorithmAES_GCMMac.cpp
>+++ b/Source/WebCore/crypto/mac/CryptoAlgorithmAES_GCMMac.cpp
>@@ -72,12 +72,12 @@ static ExceptionOr<Vector<uint8_t>> decyptAES_GCM(const Vector<uint8_t>& iv, con
> 
> ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_GCM::platformEncrypt(const CryptoAlgorithmAesGcmParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& plainText)
> {
>-    return encryptAES_GCM(parameters.ivVector(), key.key(), plainText, parameters.additionalDataVector(), parameters.tagLength.value_or(0) / 8);
>+    return encryptAES_GCM(parameters.ivVector(), key.key(), plainText, parameters.additionalDataVector(), parameters.tagLength.valueOr(0) / 8);
> }
> 
> ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_GCM::platformDecrypt(const CryptoAlgorithmAesGcmParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& cipherText)
> {
>-    return decyptAES_GCM(parameters.ivVector(), key.key(), cipherText, parameters.additionalDataVector(), parameters.tagLength.value_or(0) / 8);
>+    return decyptAES_GCM(parameters.ivVector(), key.key(), cipherText, parameters.additionalDataVector(), parameters.tagLength.valueOr(0) / 8);
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/crypto/mac/CryptoKeyRSAMac.cpp b/Source/WebCore/crypto/mac/CryptoKeyRSAMac.cpp
>index 3aa701d314723717485429ee4788bbbf9c3d0274..11a7c916b612fd6339bde37b22cce259ab6a9704 100644
>--- a/Source/WebCore/crypto/mac/CryptoKeyRSAMac.cpp
>+++ b/Source/WebCore/crypto/mac/CryptoKeyRSAMac.cpp
>@@ -363,7 +363,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importSpki(CryptoAlgorithmIdentifier identifi
>         return nullptr;
> 
>     // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-    return adoptRef(new CryptoKeyRSA(identifier, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Public, ccPublicKey, extractable, usages));
>+    return adoptRef(new CryptoKeyRSA(identifier, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Public, ccPublicKey, extractable, usages));
> }
> 
> ExceptionOr<Vector<uint8_t>> CryptoKeyRSA::exportSpki() const
>@@ -420,7 +420,7 @@ RefPtr<CryptoKeyRSA> CryptoKeyRSA::importPkcs8(CryptoAlgorithmIdentifier identif
>         return nullptr;
> 
>     // Notice: CryptoAlgorithmIdentifier::SHA_1 is just a placeholder. It should not have any effect if hash is WTF::nullopt.
>-    return adoptRef(new CryptoKeyRSA(identifier, hash.value_or(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Private, ccPrivateKey, extractable, usages));
>+    return adoptRef(new CryptoKeyRSA(identifier, hash.valueOr(CryptoAlgorithmIdentifier::SHA_1), !!hash, CryptoKeyType::Private, ccPrivateKey, extractable, usages));
> }
> 
> ExceptionOr<Vector<uint8_t>> CryptoKeyRSA::exportPkcs8() const
>diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>index 7b26e3adac5fbd61322c626f69b43d282ef43561..1d09c8a671a3699bfd90015482ff65eb72dd955a 100644
>--- a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>@@ -1951,7 +1951,7 @@ static Ref<CSSValue> counterToCSSValue(const RenderStyle& style, CSSPropertyID p
>     auto list = CSSValueList::createSpaceSeparated();
>     for (auto& keyValue : *map) {
>         list->append(cssValuePool.createValue(keyValue.key, CSSPrimitiveValue::CSS_STRING));
>-        double number = (propertyID == CSSPropertyCounterIncrement ? keyValue.value.incrementValue : keyValue.value.resetValue).value_or(0);
>+        double number = (propertyID == CSSPropertyCounterIncrement ? keyValue.value.incrementValue : keyValue.value.resetValue).valueOr(0);
>         list->append(cssValuePool.createValue(number, CSSPrimitiveValue::CSS_NUMBER));
>     }
>     return WTFMove(list);
>diff --git a/Source/WebCore/css/CSSFontFace.cpp b/Source/WebCore/css/CSSFontFace.cpp
>index 54a40480aaf1f11b604d70ace3d69e07514c390d..0eca51b3db6ef3af1177b34d5f97fbd26054ee39 100644
>--- a/Source/WebCore/css/CSSFontFace.cpp
>+++ b/Source/WebCore/css/CSSFontFace.cpp
>@@ -202,7 +202,7 @@ static FontSelectionRange calculateItalicRange(CSSValue& value)
> {
>     if (value.isFontStyleValue()) {
>         auto result = StyleBuilderConverter::convertFontStyleFromValue(value);
>-        return { result.value_or(normalItalicValue()), result.value_or(normalItalicValue()) };
>+        return { result.valueOr(normalItalicValue()), result.valueOr(normalItalicValue()) };
>     }
> 
>     ASSERT(value.isFontStyleRangeValue());
>diff --git a/Source/WebCore/css/CSSPrimitiveValue.cpp b/Source/WebCore/css/CSSPrimitiveValue.cpp
>index 6ae62671983eb70f7139b9be5c176a091bfcd0a7..06ffb60ea46ed118f32f464f64c95fc44a35732d 100644
>--- a/Source/WebCore/css/CSSPrimitiveValue.cpp
>+++ b/Source/WebCore/css/CSSPrimitiveValue.cpp
>@@ -787,7 +787,7 @@ ExceptionOr<float> CSSPrimitiveValue::getFloatValue(unsigned short unitType) con
> 
> double CSSPrimitiveValue::doubleValue(UnitType unitType) const
> {
>-    return doubleValueInternal(unitType).value_or(0);
>+    return doubleValueInternal(unitType).valueOr(0);
> }
> 
> double CSSPrimitiveValue::doubleValue() const
>diff --git a/Source/WebCore/css/CSSStyleSheet.cpp b/Source/WebCore/css/CSSStyleSheet.cpp
>index 12cda545d7bcc75dedb7a795351bd6f003674fc2..67c30e419182142c9c41c0dc546a6dfaffb6e74c 100644
>--- a/Source/WebCore/css/CSSStyleSheet.cpp
>+++ b/Source/WebCore/css/CSSStyleSheet.cpp
>@@ -316,7 +316,7 @@ ExceptionOr<int> CSSStyleSheet::addRule(const String& selector, const String& st
>     if (!style.isEmpty())
>         text.append(' ');
>     text.append('}');
>-    auto insertRuleResult = insertRule(text.toString(), index.value_or(length()));
>+    auto insertRuleResult = insertRule(text.toString(), index.valueOr(length()));
>     if (insertRuleResult.hasException())
>         return insertRuleResult.releaseException();
>     
>diff --git a/Source/WebCore/css/DOMMatrix.cpp b/Source/WebCore/css/DOMMatrix.cpp
>index c354e978273ba56e2ffb547ff3918339cd0fccaf..a00f165b48373cbae0440060ca0122a1feacda61 100644
>--- a/Source/WebCore/css/DOMMatrix.cpp
>+++ b/Source/WebCore/css/DOMMatrix.cpp
>@@ -189,8 +189,8 @@ Ref<DOMMatrix> DOMMatrix::rotateSelf(double rotX, Optional<double> rotY, Optiona
>         rotX = 0;
>         rotY = 0;
>     }
>-    m_matrix.rotate3d(rotX, rotY.value_or(0), rotZ.value_or(0));
>-    if (rotX || rotY.value_or(0))
>+    m_matrix.rotate3d(rotX, rotY.valueOr(0), rotZ.valueOr(0));
>+    if (rotX || rotY.valueOr(0))
>         m_is2D = false;
>     return *this;
> }
>diff --git a/Source/WebCore/css/DOMMatrixReadOnly.cpp b/Source/WebCore/css/DOMMatrixReadOnly.cpp
>index cc7f72698513ee8380398827d919b48f75313395..13996fb553ce1c6a8f72ba99e486de1a48dd5b03 100644
>--- a/Source/WebCore/css/DOMMatrixReadOnly.cpp
>+++ b/Source/WebCore/css/DOMMatrixReadOnly.cpp
>@@ -120,17 +120,17 @@ ExceptionOr<void> DOMMatrixReadOnly::validateAndFixup(DOMMatrix2DInit& init)
>         return Exception { TypeError, "init.f and init.m42 do not match"_s };
> 
>     if (!init.m11)
>-        init.m11 = init.a.value_or(1);
>+        init.m11 = init.a.valueOr(1);
>     if (!init.m12)
>-        init.m12 = init.b.value_or(0);
>+        init.m12 = init.b.valueOr(0);
>     if (!init.m21)
>-        init.m21 = init.c.value_or(0);
>+        init.m21 = init.c.valueOr(0);
>     if (!init.m22)
>-        init.m22 = init.d.value_or(1);
>+        init.m22 = init.d.valueOr(1);
>     if (!init.m41)
>-        init.m41 = init.e.value_or(0);
>+        init.m41 = init.e.valueOr(0);
>     if (!init.m42)
>-        init.m42 = init.f.value_or(0);
>+        init.m42 = init.f.valueOr(0);
> 
>     return { };
> }
>diff --git a/Source/WebCore/css/StyleBuilderCustom.h b/Source/WebCore/css/StyleBuilderCustom.h
>index c7852f029d838409ab4e53ac03d1029a48e94834..48e6caba89bb76a4ba81dad96b536a7d3a6c45e4 100644
>--- a/Source/WebCore/css/StyleBuilderCustom.h
>+++ b/Source/WebCore/css/StyleBuilderCustom.h
>@@ -1193,7 +1193,7 @@ inline void StyleBuilderCustom::applyValueCounter(StyleResolver& styleResolver,
>         if (counterBehavior == Reset)
>             directives.resetValue = value;
>         else
>-            directives.incrementValue = saturatedAddition(directives.incrementValue.value_or(0), value);
>+            directives.incrementValue = saturatedAddition(directives.incrementValue.valueOr(0), value);
>     }
> }
> 
>diff --git a/Source/WebCore/css/parser/MediaQueryParser.cpp b/Source/WebCore/css/parser/MediaQueryParser.cpp
>index 8c3562ecf57f59b08f263af9894edaa896e3ee82..6d21d20b1dfcc2f593bf26e6bc6e02a6a117ef72 100644
>--- a/Source/WebCore/css/parser/MediaQueryParser.cpp
>+++ b/Source/WebCore/css/parser/MediaQueryParser.cpp
>@@ -141,7 +141,7 @@ void MediaQueryParser::commitMediaQuery()
>     // FIXME-NEWPARSER: Convoluted and awful, but we can't change the MediaQuerySet yet because of the
>     // old parser.
>     static const NeverDestroyed<String> defaultMediaType { "all"_s };
>-    MediaQuery mediaQuery { m_mediaQueryData.restrictor(), m_mediaQueryData.mediaType().value_or(defaultMediaType), WTFMove(m_mediaQueryData.expressions()) };
>+    MediaQuery mediaQuery { m_mediaQueryData.restrictor(), m_mediaQueryData.mediaType().valueOr(defaultMediaType), WTFMove(m_mediaQueryData.expressions()) };
>     m_mediaQueryData.clear();
>     m_querySet->addMediaQuery(WTFMove(mediaQuery));
> }
>diff --git a/Source/WebCore/dom/Document.h b/Source/WebCore/dom/Document.h
>index 6d5cddb83f8ec20f0d856ef14bca18248037d4ce..8a0ffe10b459712274de7d7242860290737cf9ea 100644
>--- a/Source/WebCore/dom/Document.h
>+++ b/Source/WebCore/dom/Document.h
>@@ -423,7 +423,7 @@ public:
> #endif
> 
>     void setReferrerPolicy(ReferrerPolicy);
>-    ReferrerPolicy referrerPolicy() const { return m_referrerPolicy.value_or(ReferrerPolicy::NoReferrerWhenDowngrade); }
>+    ReferrerPolicy referrerPolicy() const { return m_referrerPolicy.valueOr(ReferrerPolicy::NoReferrerWhenDowngrade); }
> 
>     WEBCORE_EXPORT DocumentType* doctype() const;
> 
>diff --git a/Source/WebCore/dom/Element.cpp b/Source/WebCore/dom/Element.cpp
>index b26c41f18ea90f318ea6c7febd9f15801b680239..5ff302fbe65265586d620e26e23fe476b4652eb7 100644
>--- a/Source/WebCore/dom/Element.cpp
>+++ b/Source/WebCore/dom/Element.cpp
>@@ -657,7 +657,7 @@ void Element::setHovered(bool flag)
> // FIXME(webkit.org/b/161611): Take into account orientation/direction.
> inline ScrollAlignment toScrollAlignment(Optional<ScrollLogicalPosition> position, bool isVertical)
> {
>-    switch (position.value_or(isVertical ? ScrollLogicalPosition::Start : ScrollLogicalPosition::Nearest)) {
>+    switch (position.valueOr(isVertical ? ScrollLogicalPosition::Start : ScrollLogicalPosition::Nearest)) {
>     case ScrollLogicalPosition::Start:
>         return isVertical ? ScrollAlignment::alignTopAlways : ScrollAlignment::alignLeftAlways;
>     case ScrollLogicalPosition::Center:
>diff --git a/Source/WebCore/dom/EventTarget.cpp b/Source/WebCore/dom/EventTarget.cpp
>index ba27ad06a7ddd1170d7542b4b260dd9b4eca06fb..d1c87de5e498d59e1b2a85c698cebba1b2eb1c61 100644
>--- a/Source/WebCore/dom/EventTarget.cpp
>+++ b/Source/WebCore/dom/EventTarget.cpp
>@@ -82,7 +82,7 @@ bool EventTarget::addEventListener(const AtomicString& eventType, Ref<EventListe
>     bool listenerCreatedFromScript = listener->type() == EventListener::JSEventListenerType && !listener->wasCreatedFromMarkup();
>     auto listenerRef = listener.copyRef();
> 
>-    if (!ensureEventTargetData().eventListenerMap.add(eventType, WTFMove(listener), { options.capture, passive.value_or(false), options.once }))
>+    if (!ensureEventTargetData().eventListenerMap.add(eventType, WTFMove(listener), { options.capture, passive.valueOr(false), options.once }))
>         return false;
> 
>     if (listenerCreatedFromScript)
>diff --git a/Source/WebCore/dom/MutationObserver.cpp b/Source/WebCore/dom/MutationObserver.cpp
>index 846249536eb9ca2dbd26acdb047380fe02e53ff8..6f79a74401f0d92b5da8f397b2483e2ce06ac9a3 100644
>--- a/Source/WebCore/dom/MutationObserver.cpp
>+++ b/Source/WebCore/dom/MutationObserver.cpp
>@@ -85,9 +85,9 @@ ExceptionOr<void> MutationObserver::observe(Node& node, const Init& init)
>         options |= ChildList;
>     if (init.subtree)
>         options |= Subtree;
>-    if (init.attributeOldValue.value_or(false))
>+    if (init.attributeOldValue.valueOr(false))
>         options |= AttributeOldValue;
>-    if (init.characterDataOldValue.value_or(false))
>+    if (init.characterDataOldValue.valueOr(false))
>         options |= CharacterDataOldValue;
> 
>     HashSet<AtomicString> attributeFilter;
>diff --git a/Source/WebCore/editing/cocoa/FontAttributeChangesCocoa.mm b/Source/WebCore/editing/cocoa/FontAttributeChangesCocoa.mm
>index d431f722e24aab3bd17728b4358b78698b786f4b..da02cb2c4ceff83ad455ffb2debc662994a7e76f 100644
>--- a/Source/WebCore/editing/cocoa/FontAttributeChangesCocoa.mm
>+++ b/Source/WebCore/editing/cocoa/FontAttributeChangesCocoa.mm
>@@ -46,8 +46,8 @@ const String& FontChanges::platformFontFamilyNameForCSS() const
>     RetainPtr<CFStringRef> fontNameFromDescription;
> 
>     FontDescription description;
>-    description.setIsItalic(m_italic.value_or(false));
>-    description.setWeight(FontSelectionValue { m_bold.value_or(false) ? 900 : 500 });
>+    description.setIsItalic(m_italic.valueOr(false));
>+    description.setWeight(FontSelectionValue { m_bold.valueOr(false) ? 900 : 500 });
>     if (auto font = FontCache::singleton().fontForFamily(description, m_fontFamily))
>         fontNameFromDescription = adoptCF(CTFontCopyPostScriptName(font->getCTFont()));
> 
>diff --git a/Source/WebCore/fileapi/File.cpp b/Source/WebCore/fileapi/File.cpp
>index fc0fa57f0bedb9d759af79f458e50560848128d2..b73fcde79f460792c926c075fbaaf6648a724131 100644
>--- a/Source/WebCore/fileapi/File.cpp
>+++ b/Source/WebCore/fileapi/File.cpp
>@@ -81,7 +81,7 @@ static BlobPropertyBag convertPropertyBag(const File::PropertyBag& initialBag)
> File::File(Vector<BlobPartVariant>&& blobPartVariants, const String& filename, const PropertyBag& propertyBag)
>     : Blob(WTFMove(blobPartVariants), convertPropertyBag(propertyBag))
>     , m_name(filename)
>-    , m_lastModifiedDateOverride(propertyBag.lastModified.value_or(WallTime::now().secondsSinceEpoch().milliseconds()))
>+    , m_lastModifiedDateOverride(propertyBag.lastModified.valueOr(WallTime::now().secondsSinceEpoch().milliseconds()))
> {
> }
> 
>diff --git a/Source/WebCore/html/DOMTokenList.cpp b/Source/WebCore/html/DOMTokenList.cpp
>index cea1cd309cdc35287e84e0dd07055fbba974b449..af00911e06ecc57ed38a468322293532c35a6dfa 100644
>--- a/Source/WebCore/html/DOMTokenList.cpp
>+++ b/Source/WebCore/html/DOMTokenList.cpp
>@@ -141,7 +141,7 @@ ExceptionOr<bool> DOMTokenList::toggle(const AtomicString& token, Optional<bool>
>     auto& tokens = this->tokens();
> 
>     if (tokens.contains(token)) {
>-        if (!force.value_or(false)) {
>+        if (!force.valueOr(false)) {
>             tokens.removeFirst(token);
>             updateAssociatedAttributeFromTokens();
>             return false;
>diff --git a/Source/WebCore/html/HTMLOListElement.h b/Source/WebCore/html/HTMLOListElement.h
>index 5f4d9efdad5d3de0601a06a0fe30ab20ee2d6d3f..813f5e062db25b54319acd325599b000f959c954 100644
>--- a/Source/WebCore/html/HTMLOListElement.h
>+++ b/Source/WebCore/html/HTMLOListElement.h
>@@ -32,7 +32,7 @@ public:
>     static Ref<HTMLOListElement> create(Document&);
>     static Ref<HTMLOListElement> create(const QualifiedName&, Document&);
> 
>-    int startForBindings() const { return m_start.value_or(1); }
>+    int startForBindings() const { return m_start.valueOr(1); }
>     WEBCORE_EXPORT void setStartForBindings(int);
> 
>     // FIXME: The reason start() does not trigger layout is because it is called
>diff --git a/Source/WebCore/html/ImageBitmap.cpp b/Source/WebCore/html/ImageBitmap.cpp
>index 6b2ee1849e49ef575386dedb15efdb455c84183f..9dbbb4feec51a3b994e15ad6be682fa2382ddbb6 100644
>--- a/Source/WebCore/html/ImageBitmap.cpp
>+++ b/Source/WebCore/html/ImageBitmap.cpp
>@@ -160,7 +160,7 @@ static ExceptionOr<IntRect> croppedSourceRectangleWithFormatting(IntSize inputSi
>     //    Otherwise let sourceRectangle be a rectangle whose corners are the four points
>     //    (0,0), (width of input, 0), (width of input, height of input), (0, height of
>     //    input).
>-    auto sourceRectangle = rect.value_or(IntRect { 0, 0, inputSize.width(), inputSize.height() });
>+    auto sourceRectangle = rect.valueOr(IntRect { 0, 0, inputSize.width(), inputSize.height() });
> 
>     // 4. Clip sourceRectangle to the dimensions of input.
>     sourceRectangle.intersect(IntRect { 0, 0, inputSize.width(), inputSize.height() });
>diff --git a/Source/WebCore/html/canvas/CanvasPattern.cpp b/Source/WebCore/html/canvas/CanvasPattern.cpp
>index 9a9de9a772a71ebcd2dfbb716ca92549c44c060f..72ea1a87c6d0e26018757ee2f7bc60463c9aa805 100644
>--- a/Source/WebCore/html/canvas/CanvasPattern.cpp
>+++ b/Source/WebCore/html/canvas/CanvasPattern.cpp
>@@ -78,7 +78,7 @@ ExceptionOr<void> CanvasPattern::setTransform(DOMMatrix2DInit&& matrixInit)
>     if (checkValid.hasException())
>         return checkValid.releaseException();
> 
>-    m_pattern->setPatternSpaceTransform({ matrixInit.a.value_or(1), matrixInit.b.value_or(0), matrixInit.c.value_or(0), matrixInit.d.value_or(1), matrixInit.e.value_or(0), matrixInit.f.value_or(0) });
>+    m_pattern->setPatternSpaceTransform({ matrixInit.a.valueOr(1), matrixInit.b.valueOr(0), matrixInit.c.valueOr(0), matrixInit.d.valueOr(1), matrixInit.e.valueOr(0), matrixInit.f.valueOr(0) });
>     return { };
> }
> 
>diff --git a/Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp b/Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp
>index 2286d3222abd7cf0e80e121d80d86edb60cd52dc..d426fac61339fec3c13f4e706dacfabd518799db 100644
>--- a/Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp
>+++ b/Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp
>@@ -915,7 +915,7 @@ ExceptionOr<void> CanvasRenderingContext2DBase::setTransform(DOMMatrix2DInit&& m
>     if (checkValid.hasException())
>         return checkValid.releaseException();
> 
>-    setTransform(matrixInit.a.value_or(1), matrixInit.b.value_or(0), matrixInit.c.value_or(0), matrixInit.d.value_or(1), matrixInit.e.value_or(0), matrixInit.f.value_or(0));
>+    setTransform(matrixInit.a.valueOr(1), matrixInit.b.valueOr(0), matrixInit.c.valueOr(0), matrixInit.d.valueOr(1), matrixInit.e.valueOr(0), matrixInit.f.valueOr(0));
>     return { };
> }
> 
>@@ -1204,7 +1204,7 @@ bool CanvasRenderingContext2DBase::isPointInPathInternal(const Path& path, float
>     if (!state().hasInvertibleTransform)
>         return false;
> 
>-    auto transformedPoint = state().transform.inverse().value_or(AffineTransform()).mapPoint(FloatPoint(x, y));
>+    auto transformedPoint = state().transform.inverse().valueOr(AffineTransform()).mapPoint(FloatPoint(x, y));
> 
>     if (!std::isfinite(transformedPoint.x()) || !std::isfinite(transformedPoint.y()))
>         return false;
>@@ -1220,7 +1220,7 @@ bool CanvasRenderingContext2DBase::isPointInStrokeInternal(const Path& path, flo
>     if (!state().hasInvertibleTransform)
>         return false;
> 
>-    auto transformedPoint = state().transform.inverse().value_or(AffineTransform()).mapPoint(FloatPoint(x, y));
>+    auto transformedPoint = state().transform.inverse().valueOr(AffineTransform()).mapPoint(FloatPoint(x, y));
>     if (!std::isfinite(transformedPoint.x()) || !std::isfinite(transformedPoint.y()))
>         return false;
> 
>diff --git a/Source/WebCore/html/canvas/Path2D.cpp b/Source/WebCore/html/canvas/Path2D.cpp
>index 215b7d3bad2b854331f64b3f1c03345f2c2ce057..385e9dabf5dcbca3bd22feaa95f784d2f4794b31 100644
>--- a/Source/WebCore/html/canvas/Path2D.cpp
>+++ b/Source/WebCore/html/canvas/Path2D.cpp
>@@ -42,7 +42,7 @@ ExceptionOr<void> Path2D::addPath(Path2D& path, DOMMatrix2DInit&& matrixInit)
>     if (checkValid.hasException())
>         return checkValid.releaseException();
> 
>-    m_path.addPath(path.path(), { matrixInit.a.value_or(1), matrixInit.b.value_or(0), matrixInit.c.value_or(0), matrixInit.d.value_or(1), matrixInit.e.value_or(0), matrixInit.f.value_or(0) });
>+    m_path.addPath(path.path(), { matrixInit.a.valueOr(1), matrixInit.b.valueOr(0), matrixInit.c.valueOr(0), matrixInit.d.valueOr(1), matrixInit.e.valueOr(0), matrixInit.f.valueOr(0) });
>     return { };
> }
> 
>diff --git a/Source/WebCore/inspector/InspectorCanvas.cpp b/Source/WebCore/inspector/InspectorCanvas.cpp
>index 9b68c4b05c3b63ea1eff71b01ae9b159fbce67d3..52b0bcb9b22b488a1012218cc622778f0672e3b7 100644
>--- a/Source/WebCore/inspector/InspectorCanvas.cpp
>+++ b/Source/WebCore/inspector/InspectorCanvas.cpp
>@@ -582,12 +582,12 @@ Ref<JSON::ArrayOf<JSON::Value>> InspectorCanvas::buildAction(const String& name,
>             [&] (CanvasTextBaseline value) { addParameter(indexForData(convertEnumerationToString(value)), RecordingSwizzleTypes::String); },
>             [&] (const DOMMatrix2DInit& value) {
>                 auto array = JSON::ArrayOf<double>::create();
>-                array->addItem(value.a.value_or(1));
>-                array->addItem(value.b.value_or(0));
>-                array->addItem(value.c.value_or(0));
>-                array->addItem(value.d.value_or(1));
>-                array->addItem(value.e.value_or(0));
>-                array->addItem(value.f.value_or(0));
>+                array->addItem(value.a.valueOr(1));
>+                array->addItem(value.b.valueOr(0));
>+                array->addItem(value.c.valueOr(0));
>+                array->addItem(value.d.valueOr(1));
>+                array->addItem(value.e.valueOr(0));
>+                array->addItem(value.f.valueOr(0));
>                 addParameter(array.ptr(), RecordingSwizzleTypes::DOMMatrix);
>             },
>             [&] (const Element*) {
>diff --git a/Source/WebCore/inspector/InspectorFrontendHost.cpp b/Source/WebCore/inspector/InspectorFrontendHost.cpp
>index 874f384c3a3f7c14cc4ac36a2a1f08a8c59ec861..c080a56c6861f3e398979a7b123d562b8b90f46a 100644
>--- a/Source/WebCore/inspector/InspectorFrontendHost.cpp
>+++ b/Source/WebCore/inspector/InspectorFrontendHost.cpp
>@@ -373,7 +373,7 @@ static void populateContextMenu(Vector<InspectorFrontendHost::ContextMenuItem>&&
>         }
> 
>         auto type = item.type == "checkbox" ? CheckableActionType : ActionType;
>-        auto action = static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + item.id.value_or(0));
>+        auto action = static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + item.id.valueOr(0));
>         ContextMenuItem menuItem = { type, action, item.label };
>         if (item.enabled)
>             menuItem.setEnabled(*item.enabled);
>diff --git a/Source/WebCore/layout/FormattingContext.cpp b/Source/WebCore/layout/FormattingContext.cpp
>index b3c57624eb15f6f2d03847e8184c7d0eb8767b99..11efc4618b91aa8f61ff0325ca76480e48c95926 100644
>--- a/Source/WebCore/layout/FormattingContext.cpp
>+++ b/Source/WebCore/layout/FormattingContext.cpp
>@@ -224,16 +224,16 @@ void FormattingContext::validateGeometryConstraintsAfterLayout() const
>         if ((layoutBox.isBlockLevelBox() || layoutBox.isOutOfFlowPositioned()) && !layoutBox.replaced()) {
>             // margin-left + border-left-width + padding-left + width + padding-right + border-right-width + margin-right = width of containing block
>             auto containingBlockWidth = containingBlockDisplayBox.contentBoxWidth();
>-            ASSERT(displayBox.marginStart() + displayBox.borderLeft() + displayBox.paddingLeft().value_or(0) + displayBox.contentBoxWidth()
>-                + displayBox.paddingRight().value_or(0) + displayBox.borderRight() + displayBox.marginEnd() == containingBlockWidth);
>+            ASSERT(displayBox.marginStart() + displayBox.borderLeft() + displayBox.paddingLeft().valueOr(0) + displayBox.contentBoxWidth()
>+                + displayBox.paddingRight().valueOr(0) + displayBox.borderRight() + displayBox.marginEnd() == containingBlockWidth);
>         }
> 
>         // 10.6.4 Absolutely positioned, non-replaced elements
>         if (layoutBox.isOutOfFlowPositioned() && !layoutBox.replaced()) {
>             // top + margin-top + border-top-width + padding-top + height + padding-bottom + border-bottom-width + margin-bottom + bottom = height of containing block
>             auto containingBlockHeight = containingBlockDisplayBox.contentBoxHeight();
>-            ASSERT(displayBox.top() + displayBox.marginBefore() + displayBox.borderTop() + displayBox.paddingTop().value_or(0) + displayBox.contentBoxHeight()
>-                + displayBox.paddingBottom().value_or(0) + displayBox.borderBottom() + displayBox.marginAfter() == containingBlockHeight);
>+            ASSERT(displayBox.top() + displayBox.marginBefore() + displayBox.borderTop() + displayBox.paddingTop().valueOr(0) + displayBox.contentBoxHeight()
>+                + displayBox.paddingBottom().valueOr(0) + displayBox.borderBottom() + displayBox.marginAfter() == containingBlockHeight);
>         }
>     }
> }
>diff --git a/Source/WebCore/layout/FormattingContextGeometry.cpp b/Source/WebCore/layout/FormattingContextGeometry.cpp
>index e03d83d073880f592629c54966576e1b36c212c8..c339f9780fc40eff608f92579cc4700d911e4e3e 100644
>--- a/Source/WebCore/layout/FormattingContextGeometry.cpp
>+++ b/Source/WebCore/layout/FormattingContextGeometry.cpp
>@@ -282,8 +282,8 @@ VerticalGeometry FormattingContext::Geometry::outOfFlowNonReplacedVerticalGeomet
>     auto height = usedHeight ? usedHeight.value() : computedHeightValue(layoutState, layoutBox, HeightType::Normal);
>     auto marginBefore = computedValueIfNotAuto(style.marginBefore(), containingBlockWidth);
>     auto marginAfter = computedValueIfNotAuto(style.marginAfter(), containingBlockWidth);
>-    auto paddingTop = displayBox.paddingTop().value_or(0);
>-    auto paddingBottom = displayBox.paddingBottom().value_or(0);
>+    auto paddingTop = displayBox.paddingTop().valueOr(0);
>+    auto paddingBottom = displayBox.paddingBottom().valueOr(0);
>     auto borderTop = displayBox.borderTop();
>     auto borderBottom = displayBox.borderBottom();
> 
>@@ -307,45 +307,45 @@ VerticalGeometry FormattingContext::Geometry::outOfFlowNonReplacedVerticalGeomet
>     if (!top && !height && bottom) {
>         // #1
>         height = contentHeightForFormattingContextRoot(layoutState, layoutBox);
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         top = containingBlockHeight - (*marginBefore + borderTop + paddingTop + *height + paddingBottom + borderBottom + *marginAfter + *bottom); 
>     }
> 
>     if (!top && !bottom && height) {
>         // #2
>         top = staticVerticalPositionForOutOfFlowPositioned(layoutState, layoutBox);
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         bottom = containingBlockHeight - (*top + *marginBefore + borderTop + paddingTop + *height + paddingBottom + borderBottom + *marginAfter); 
>     }
> 
>     if (!height && !bottom && top) {
>         // #3
>         height = contentHeightForFormattingContextRoot(layoutState, layoutBox);
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         bottom = containingBlockHeight - (*top + *marginBefore + borderTop + paddingTop + *height + paddingBottom + borderBottom + *marginAfter); 
>     }
> 
>     if (!top && height && bottom) {
>         // #4
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         top = containingBlockHeight - (*marginBefore + borderTop + paddingTop + *height + paddingBottom + borderBottom + *marginAfter + *bottom); 
>     }
> 
>     if (!height && top && bottom) {
>         // #5
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         height = containingBlockHeight - (*top + *marginBefore + borderTop + paddingTop + paddingBottom + borderBottom + *marginAfter + *bottom); 
>     }
> 
>     if (!bottom && top && height) {
>         // #6
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>         bottom = containingBlockHeight - (*top + *marginBefore + borderTop + paddingTop + *height + paddingBottom + borderBottom + *marginAfter); 
>     }
> 
>@@ -400,10 +400,10 @@ HorizontalGeometry FormattingContext::Geometry::outOfFlowNonReplacedHorizontalGe
>     auto width = computedValueIfNotAuto(usedWidth ? Length { usedWidth.value(), Fixed } : style.logicalWidth(), containingBlockWidth);
>     auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth);
>     auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth);
>-    auto nonComputedMarginStart = marginStart.value_or(0);
>-    auto nonComputedMarginEnd = marginEnd.value_or(0);
>-    auto paddingLeft = displayBox.paddingLeft().value_or(0);
>-    auto paddingRight = displayBox.paddingRight().value_or(0);
>+    auto nonComputedMarginStart = marginStart.valueOr(0);
>+    auto nonComputedMarginEnd = marginEnd.valueOr(0);
>+    auto paddingLeft = displayBox.paddingLeft().valueOr(0);
>+    auto paddingRight = displayBox.paddingRight().valueOr(0);
>     auto borderLeft = displayBox.borderLeft();
>     auto borderRight = displayBox.borderRight();
> 
>@@ -411,8 +411,8 @@ HorizontalGeometry FormattingContext::Geometry::outOfFlowNonReplacedHorizontalGe
>         // If all three of 'left', 'width', and 'right' are 'auto': First set any 'auto' values for 'margin-left' and 'margin-right' to 0.
>         // Then, if the 'direction' property of the element establishing the static-position containing block is 'ltr' set 'left' to the static
>         // position and apply rule number three below; otherwise, set 'right' to the static position and apply rule number one below.
>-        marginStart = marginStart.value_or(0);
>-        marginEnd = marginEnd.value_or(0);
>+        marginStart = marginStart.valueOr(0);
>+        marginEnd = marginEnd.valueOr(0);
> 
>         auto staticHorizontalPosition = staticHorizontalPositionForOutOfFlowPositioned(layoutState, layoutBox);
>         if (isLeftToRightDirection)
>@@ -459,8 +459,8 @@ HorizontalGeometry FormattingContext::Geometry::outOfFlowNonReplacedHorizontalGe
>         }
>     } else {
>         // Otherwise, set 'auto' values for 'margin-left' and 'margin-right' to 0, and pick the one of the following six rules that applies.
>-        marginStart = marginStart.value_or(0);
>-        marginEnd = marginEnd.value_or(0);
>+        marginStart = marginStart.valueOr(0);
>+        marginEnd = marginEnd.valueOr(0);
>     }
> 
>     ASSERT(marginStart);
>@@ -530,8 +530,8 @@ VerticalGeometry FormattingContext::Geometry::outOfFlowReplacedVerticalGeometry(
>     auto height = inlineReplacedHeightAndMargin(layoutState, layoutBox, usedHeight).height;
>     auto marginBefore = computedValueIfNotAuto(style.marginBefore(), containingBlockWidth);
>     auto marginAfter = computedValueIfNotAuto(style.marginAfter(), containingBlockWidth);
>-    auto paddingTop = displayBox.paddingTop().value_or(0);
>-    auto paddingBottom = displayBox.paddingBottom().value_or(0);
>+    auto paddingTop = displayBox.paddingTop().valueOr(0);
>+    auto paddingBottom = displayBox.paddingBottom().valueOr(0);
>     auto borderTop = displayBox.borderTop();
>     auto borderBottom = displayBox.borderBottom();
> 
>@@ -542,8 +542,8 @@ VerticalGeometry FormattingContext::Geometry::outOfFlowReplacedVerticalGeometry(
> 
>     if (!bottom) {
>         // #2
>-        marginBefore = marginBefore.value_or(0);
>-        marginAfter = marginAfter.value_or(0);
>+        marginBefore = marginBefore.valueOr(0);
>+        marginAfter = marginAfter.valueOr(0);
>     }
> 
>     if (!marginBefore && !marginAfter) {
>@@ -602,11 +602,11 @@ HorizontalGeometry FormattingContext::Geometry::outOfFlowReplacedHorizontalGeome
>     auto right = computedValueIfNotAuto(style.logicalRight(), containingBlockWidth);
>     auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth);
>     auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth);
>-    auto nonComputedMarginStart = marginStart.value_or(0);
>-    auto nonComputedMarginEnd = marginEnd.value_or(0);
>+    auto nonComputedMarginStart = marginStart.valueOr(0);
>+    auto nonComputedMarginEnd = marginEnd.valueOr(0);
>     auto width = inlineReplacedWidthAndMargin(layoutState, layoutBox, usedWidth).width;
>-    auto paddingLeft = displayBox.paddingLeft().value_or(0);
>-    auto paddingRight = displayBox.paddingRight().value_or(0);
>+    auto paddingLeft = displayBox.paddingLeft().valueOr(0);
>+    auto paddingRight = displayBox.paddingRight().valueOr(0);
>     auto borderLeft = displayBox.borderLeft();
>     auto borderRight = displayBox.borderRight();
> 
>@@ -621,8 +621,8 @@ HorizontalGeometry FormattingContext::Geometry::outOfFlowReplacedHorizontalGeome
> 
>     if (!left || !right) {
>         // #2
>-        marginStart = marginStart.value_or(0); 
>-        marginEnd = marginEnd.value_or(0); 
>+        marginStart = marginStart.valueOr(0); 
>+        marginEnd = marginEnd.valueOr(0); 
>     }
> 
>     if (!marginStart && !marginEnd) {
>@@ -697,8 +697,8 @@ HeightAndMargin FormattingContext::Geometry::complicatedCases(const LayoutState&
>     auto marginAfter = computedValueIfNotAuto(style.marginAfter(), containingBlockWidth);
> 
>     // #1
>-    marginBefore = marginBefore.value_or(0);
>-    marginAfter = marginAfter.value_or(0);
>+    marginBefore = marginBefore.valueOr(0);
>+    marginAfter = marginAfter.valueOr(0);
>     // #2
>     if (!height) {
>         ASSERT(isHeightAuto(layoutBox));
>@@ -873,14 +873,14 @@ WidthAndMargin FormattingContext::Geometry::inlineReplacedWidthAndMargin(const L
>         if (precomputedMarginEnd)
>             return precomputedMarginEnd.value();
>         auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth);
>-        return marginEnd.value_or(0_lu);
>+        return marginEnd.valueOr(0_lu);
>     };
> 
>     auto computeMarginStart = [&]() {
>         if (precomputedMarginStart)
>             return precomputedMarginStart.value();
>         auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth);
>-        return marginStart.value_or(0_lu);
>+        return marginStart.valueOr(0_lu);
>     };
> 
>     auto replaced = layoutBox.replaced();
>@@ -888,8 +888,8 @@ WidthAndMargin FormattingContext::Geometry::inlineReplacedWidthAndMargin(const L
> 
>     auto marginStart = computeMarginStart();
>     auto marginEnd = computeMarginEnd();
>-    auto nonComputedMarginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth).value_or(0);
>-    auto nonComputedMarginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth).value_or(0);
>+    auto nonComputedMarginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth).valueOr(0);
>+    auto nonComputedMarginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth).valueOr(0);
>     auto width = computedValueIfNotAuto(usedWidth ? Length { usedWidth.value(), Fixed } : style.logicalWidth(), containingBlockWidth);
> 
>     auto heightIsAuto = isHeightAuto(layoutBox);
>@@ -901,7 +901,7 @@ WidthAndMargin FormattingContext::Geometry::inlineReplacedWidthAndMargin(const L
>     } else if ((!width && heightIsAuto && !replaced->hasIntrinsicWidth() && replaced->hasIntrinsicHeight() && replaced->hasIntrinsicRatio())
>         || (!width && height && replaced->hasIntrinsicRatio())) {
>         // #2
>-        width = height.value_or(replaced->hasIntrinsicHeight()) * replaced->intrinsicRatio();
>+        width = height.valueOr(replaced->hasIntrinsicHeight()) * replaced->intrinsicRatio();
>     } else if (!width && heightIsAuto && replaced->hasIntrinsicRatio() && !replaced->hasIntrinsicWidth() && !replaced->hasIntrinsicHeight()) {
>         // #3
>         // FIXME: undefined but surely doable.
>@@ -990,7 +990,7 @@ LayoutSize FormattingContext::Geometry::inFlowPositionedPositionOffset(const Lay
>     ASSERT(!left || *left == -*right);
> 
>     auto topPositionOffset = *top;
>-    auto leftPositionOffset = left.value_or(-*right);
>+    auto leftPositionOffset = left.valueOr(-*right);
> 
>     LOG_WITH_STREAM(FormattingContextLayout, stream << "[Position] -> positioned inflow -> top offset(" << topPositionOffset << "px) left offset(" << leftPositionOffset << "px) layoutBox(" << &layoutBox << ")");
>     return { leftPositionOffset, topPositionOffset };
>@@ -1025,8 +1025,8 @@ HorizontalMargin FormattingContext::Geometry::computedNonCollapsedHorizontalMarg
>     auto& style = layoutBox.style();
>     auto containingBlockWidth = layoutState.displayBoxForLayoutBox(*layoutBox.containingBlock()).contentBoxWidth();
> 
>-    auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth).value_or(0_lu);
>-    auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth).value_or(0_lu);
>+    auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth).valueOr(0_lu);
>+    auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth).valueOr(0_lu);
> 
>     LOG_WITH_STREAM(FormattingContextLayout, stream << "[Margin] -> non collapsed horizontal -> margin(" << marginStart << "px, " << marginEnd << "px) -> layoutBox: " << &layoutBox);
>     return { marginStart, marginEnd };
>@@ -1037,8 +1037,8 @@ VerticalMargin::ComputedValues FormattingContext::Geometry::computedNonCollapsed
>     auto& style = layoutBox.style();
>     auto containingBlockWidth = layoutState.displayBoxForLayoutBox(*layoutBox.containingBlock()).contentBoxWidth();
> 
>-    auto marginBefore = computedValueIfNotAuto(style.marginBefore(), containingBlockWidth).value_or(0_lu);
>-    auto marginAfter = computedValueIfNotAuto(style.marginAfter(), containingBlockWidth).value_or(0_lu);
>+    auto marginBefore = computedValueIfNotAuto(style.marginBefore(), containingBlockWidth).valueOr(0_lu);
>+    auto marginAfter = computedValueIfNotAuto(style.marginAfter(), containingBlockWidth).valueOr(0_lu);
> 
>     LOG_WITH_STREAM(FormattingContextLayout, stream << "[Margin] -> non collapsed vertical -> margin(" << marginBefore << "px, " << marginAfter << "px) -> layoutBox: " << &layoutBox);
>     return { marginBefore, marginAfter };
>diff --git a/Source/WebCore/layout/FormattingContextQuirks.cpp b/Source/WebCore/layout/FormattingContextQuirks.cpp
>index d10abe27655ad9d9b939eda108c1a1534dcb9829..b4f44a825ef3aa58ad2b36a0e2ad21475f2e87d5 100644
>--- a/Source/WebCore/layout/FormattingContextQuirks.cpp
>+++ b/Source/WebCore/layout/FormattingContextQuirks.cpp
>@@ -52,7 +52,7 @@ LayoutUnit FormattingContext::Quirks::heightValueOfNearestContainingBlockWithFix
>             auto& displayBox = layoutState.displayBoxForLayoutBox(*containingBlock);
> 
>             auto verticalMargin = FormattingContext::Geometry::computedNonCollapsedVerticalMarginValue(layoutState, *containingBlock);
>-            auto verticalPadding = displayBox.paddingTop().value_or(0) + displayBox.paddingBottom().value_or(0);
>+            auto verticalPadding = displayBox.paddingTop().valueOr(0) + displayBox.paddingBottom().valueOr(0);
>             auto verticalBorder = displayBox.borderTop() + displayBox.borderBottom();
>             bodyAndDocumentVerticalMarginPaddingAndBorder += verticalMargin.before + verticalMargin.after + verticalPadding + verticalBorder;
>         }
>diff --git a/Source/WebCore/layout/MarginTypes.h b/Source/WebCore/layout/MarginTypes.h
>index fe68f2979a581031cffa4ee8d0782f9303f00d6e..85ffed6596867893f7d6e7df586524d687c31497 100644
>--- a/Source/WebCore/layout/MarginTypes.h
>+++ b/Source/WebCore/layout/MarginTypes.h
>@@ -80,8 +80,8 @@ inline VerticalMargin::ComputedValues VerticalMargin::usedValues() const
> {
>     if (!m_collapsed)
>         return m_nonCollapsed;
>-    return { m_collapsed->before.value_or(m_nonCollapsed.before),
>-        m_collapsed->after.value_or(m_nonCollapsed.after) };
>+    return { m_collapsed->before.valueOr(m_nonCollapsed.before),
>+        m_collapsed->after.valueOr(m_nonCollapsed.after) };
> }
> 
> }
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp b/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp
>index 56fab5523b48ccf290b2e088bda827ec9123e3af..ee43872eab6e500be8ac72b15af9010beebf8106 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp
>@@ -61,10 +61,10 @@ HeightAndMargin BlockFormattingContext::Geometry::inFlowNonReplacedHeightAndMarg
>         auto containingBlockWidth = layoutState.displayBoxForLayoutBox(*layoutBox.containingBlock()).contentBoxWidth();
>         auto& displayBox = layoutState.displayBoxForLayoutBox(layoutBox);
> 
>-        auto nonCollapsedMargin = VerticalMargin::ComputedValues { computedValueIfNotAuto(style.marginBefore(), containingBlockWidth).value_or(0),
>-            computedValueIfNotAuto(style.marginAfter(), containingBlockWidth).value_or(0) }; 
>+        auto nonCollapsedMargin = VerticalMargin::ComputedValues { computedValueIfNotAuto(style.marginBefore(), containingBlockWidth).valueOr(0),
>+            computedValueIfNotAuto(style.marginAfter(), containingBlockWidth).valueOr(0) }; 
>         auto collapsedMargin = VerticalMargin::CollapsedValues { MarginCollapse::marginBefore(layoutState, layoutBox), MarginCollapse::marginAfter(layoutState, layoutBox) };
>-        auto borderAndPaddingTop = displayBox.borderTop() + displayBox.paddingTop().value_or(0);
>+        auto borderAndPaddingTop = displayBox.borderTop() + displayBox.paddingTop().valueOr(0);
> 
>         auto height = usedHeight ? usedHeight.value() : computedHeightValue(layoutState, layoutBox, HeightType::Normal);
>         if (height)
>@@ -143,19 +143,19 @@ WidthAndMargin BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin
>         auto width = computedValueIfNotAuto(usedWidth ? Length { usedWidth.value(), Fixed } : style.logicalWidth(), containingBlockWidth);
>         auto marginStart = computedValueIfNotAuto(style.marginStart(), containingBlockWidth);
>         auto marginEnd = computedValueIfNotAuto(style.marginEnd(), containingBlockWidth);
>-        auto nonComputedMarginStart = marginStart.value_or(0);
>-        auto nonComputedMarginEnd = marginEnd.value_or(0);
>+        auto nonComputedMarginStart = marginStart.valueOr(0);
>+        auto nonComputedMarginEnd = marginEnd.valueOr(0);
>         auto borderLeft = displayBox.borderLeft();
>         auto borderRight = displayBox.borderRight();
>-        auto paddingLeft = displayBox.paddingLeft().value_or(0);
>-        auto paddingRight = displayBox.paddingRight().value_or(0);
>+        auto paddingLeft = displayBox.paddingLeft().valueOr(0);
>+        auto paddingRight = displayBox.paddingRight().valueOr(0);
> 
>         // #1
>         if (width) {
>-            auto horizontalSpaceForMargin = containingBlockWidth - (marginStart.value_or(0) + borderLeft + paddingLeft + *width + paddingRight + borderRight + marginEnd.value_or(0));
>+            auto horizontalSpaceForMargin = containingBlockWidth - (marginStart.valueOr(0) + borderLeft + paddingLeft + *width + paddingRight + borderRight + marginEnd.valueOr(0));
>             if (horizontalSpaceForMargin < 0) {
>-                marginStart = marginStart.value_or(0);
>-                marginEnd = marginEnd.value_or(0);
>+                marginStart = marginStart.valueOr(0);
>+                marginEnd = marginEnd.valueOr(0);
>             }
>         }
> 
>@@ -177,8 +177,8 @@ WidthAndMargin BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin
> 
>         // #4
>         if (!width) {
>-            marginStart = marginStart.value_or(0);
>-            marginEnd = marginEnd.value_or(0);
>+            marginStart = marginStart.valueOr(0);
>+            marginEnd = marginEnd.valueOr(0);
>             width = containingBlockWidth - (*marginStart + borderLeft + paddingLeft + paddingRight + borderRight + *marginEnd);
>         }
> 
>@@ -308,12 +308,12 @@ FormattingContext::InstrinsicWidthConstraints BlockFormattingContext::Geometry::
>         ASSERT(childInstrinsicWidthConstraints);
>         
>         auto& style = child.style();
>-        auto horizontalMarginBorderAndPadding = fixedValue(style.marginStart()).value_or(0)
>+        auto horizontalMarginBorderAndPadding = fixedValue(style.marginStart()).valueOr(0)
>             + LayoutUnit { style.borderLeftWidth() }
>-            + fixedValue(style.paddingLeft()).value_or(0)
>-            + fixedValue(style.paddingRight()).value_or(0)
>+            + fixedValue(style.paddingLeft()).valueOr(0)
>+            + fixedValue(style.paddingRight()).valueOr(0)
>             + LayoutUnit { style.borderRightWidth() }
>-            + fixedValue(style.marginEnd()).value_or(0);
>+            + fixedValue(style.marginEnd()).valueOr(0);
> 
>         minimumIntrinsicWidth = std::max(minimumIntrinsicWidth, childInstrinsicWidthConstraints->minimum + horizontalMarginBorderAndPadding); 
>         maximumIntrinsicWidth = std::max(maximumIntrinsicWidth, childInstrinsicWidthConstraints->maximum + horizontalMarginBorderAndPadding); 
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingContextQuirks.cpp b/Source/WebCore/layout/blockformatting/BlockFormattingContextQuirks.cpp
>index fb71b7c080ff3e98ddb3cc499b03e0ec09df6dfe..4606f9dc6628ee03f30c7a95f439fb13e740709d 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingContextQuirks.cpp
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingContextQuirks.cpp
>@@ -73,7 +73,7 @@ HeightAndMargin BlockFormattingContext::Quirks::stretchedHeight(const LayoutStat
>     auto& documentBox = layoutBox.isDocumentBox() ? layoutBox : *layoutBox.parent();
>     auto& documentBoxDisplayBox = layoutState.displayBoxForLayoutBox(documentBox);
>     auto documentBoxVerticalBorders = documentBoxDisplayBox.borderTop() + documentBoxDisplayBox.borderBottom();
>-    auto documentBoxVerticalPaddings = documentBoxDisplayBox.paddingTop().value_or(0) + documentBoxDisplayBox.paddingBottom().value_or(0);
>+    auto documentBoxVerticalPaddings = documentBoxDisplayBox.paddingTop().valueOr(0) + documentBoxDisplayBox.paddingBottom().valueOr(0);
> 
>     auto strechedHeight = layoutState.displayBoxForLayoutBox(initialContainingBlock(layoutBox)).contentBoxHeight();
>     strechedHeight -= documentBoxVerticalBorders + documentBoxVerticalPaddings;
>diff --git a/Source/WebCore/layout/displaytree/DisplayBox.h b/Source/WebCore/layout/displaytree/DisplayBox.h
>index fde094b3c58a85823b0d20b9f60a879bf831b21a..56392f47ee79e30d3f0e21894d3f14bb875d7e89 100644
>--- a/Source/WebCore/layout/displaytree/DisplayBox.h
>+++ b/Source/WebCore/layout/displaytree/DisplayBox.h
>@@ -133,8 +133,8 @@ public:
>     LayoutPoint bottomRight() const { return { right(), bottom() }; }
> 
>     LayoutSize size() const { return { width(), height() }; }
>-    LayoutUnit width() const { return borderLeft() + paddingLeft().value_or(0) + contentBoxWidth() + paddingRight().value_or(0) + borderRight(); }
>-    LayoutUnit height() const { return borderTop() + paddingTop().value_or(0) + contentBoxHeight() + paddingBottom().value_or(0) + borderBottom(); }
>+    LayoutUnit width() const { return borderLeft() + paddingLeft().valueOr(0) + contentBoxWidth() + paddingRight().valueOr(0) + borderRight(); }
>+    LayoutUnit height() const { return borderTop() + paddingTop().valueOr(0) + contentBoxHeight() + paddingBottom().valueOr(0) + borderBottom(); }
>     Rect rect() const { return { top(), left(), width(), height() }; }
>     Rect rectWithMargin() const { return { top() - marginBefore(), left() - marginStart(), marginStart() + width() + marginEnd(), marginBefore() + height() + marginAfter() }; }
> 
>@@ -161,8 +161,8 @@ public:
>     Optional<LayoutUnit> paddingBottom() const;
>     Optional<LayoutUnit> paddingRight() const;
> 
>-    LayoutUnit contentBoxTop() const { return borderTop() + paddingTop().value_or(0); }
>-    LayoutUnit contentBoxLeft() const { return borderLeft() + paddingLeft().value_or(0); }
>+    LayoutUnit contentBoxTop() const { return borderTop() + paddingTop().valueOr(0); }
>+    LayoutUnit contentBoxLeft() const { return borderLeft() + paddingLeft().valueOr(0); }
>     LayoutUnit contentBoxBottom() const { return contentBoxTop() + contentBoxHeight(); }
>     LayoutUnit contentBoxRight() const { return contentBoxLeft() + contentBoxWidth(); }
>     LayoutUnit contentBoxHeight() const;
>diff --git a/Source/WebCore/layout/floats/FloatingContext.cpp b/Source/WebCore/layout/floats/FloatingContext.cpp
>index d9dc8e6c3da511cfafa4f294fac844b84738e9ec..71fc0606522780dbad23a98f5994a8538ca32e39 100644
>--- a/Source/WebCore/layout/floats/FloatingContext.cpp
>+++ b/Source/WebCore/layout/floats/FloatingContext.cpp
>@@ -464,7 +464,7 @@ void Iterator::set(PositionInContextRoot verticalPosition)
> 
>         auto index = floatingType == Float::Left ? m_current.m_leftIndex : m_current.m_rightIndex;
>         // Start from the end if we don't have current yet.
>-        index = index.value_or(m_floats.size());
>+        index = index.valueOr(m_floats.size());
>         while (true) {
>             index = previousFloatingIndex(floatingType, m_floats, *index);
>             if (!index)
>diff --git a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>index 6f86264efefd031712c009fb28eb498b43fd3b0c..e21b874072756ade164bb8f70605759805069743 100644
>--- a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>+++ b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>@@ -264,7 +264,7 @@ void InlineFormattingContext::appendContentToLine(Line& line, const InlineRunPro
>     line.appendContent(run, runSize);
> 
>     if (root().style().textAlign() == TextAlignMode::Justify)
>-        Geometry::computeExpansionOpportunities(line, run, lastRunType.value_or(InlineRunProvider::Run::Type::NonWhitespace));
>+        Geometry::computeExpansionOpportunities(line, run, lastRunType.valueOr(InlineRunProvider::Run::Type::NonWhitespace));
> }
> 
> void InlineFormattingContext::layoutInlineContent(const InlineRunProvider& inlineRunProvider) const
>@@ -415,7 +415,7 @@ void InlineFormattingContext::placeInFlowPositionedChildren(unsigned fistRunInde
>             for (auto* box = &layoutBox; box != &root(); box = box->parent()) {
>                 if (!box->isInFlowPositioned())
>                     continue;
>-                offset = offset.value_or(LayoutSize()) + Geometry::inFlowPositionedPositionOffset(layoutState(), *box);
>+                offset = offset.valueOr(LayoutSize()) + Geometry::inFlowPositionedPositionOffset(layoutState(), *box);
>             }
>             return offset;
>         };
>diff --git a/Source/WebCore/loader/FrameLoader.cpp b/Source/WebCore/loader/FrameLoader.cpp
>index 0d673e9091a4b19c1754dff13e274119e4cadda5..2dbe6ae806a5bbd32db1b61070bf7276f2e370d6 100644
>--- a/Source/WebCore/loader/FrameLoader.cpp
>+++ b/Source/WebCore/loader/FrameLoader.cpp
>@@ -384,7 +384,7 @@ void FrameLoader::urlSelected(const URL& url, const String& passedTarget, Event*
>     auto* frame = lexicalFrameFromCommonVM();
>     auto initiatedByMainFrame = frame && frame->isMainFrame() ? InitiatedByMainFrame::Yes : InitiatedByMainFrame::Unknown;
> 
>-    NewFrameOpenerPolicy newFrameOpenerPolicy = openerPolicy.value_or(shouldSendReferrer == NeverSendReferrer ? NewFrameOpenerPolicy::Suppress : NewFrameOpenerPolicy::Allow);
>+    NewFrameOpenerPolicy newFrameOpenerPolicy = openerPolicy.valueOr(shouldSendReferrer == NeverSendReferrer ? NewFrameOpenerPolicy::Suppress : NewFrameOpenerPolicy::Allow);
>     urlSelected(FrameLoadRequest(*m_frame.document(), m_frame.document()->securityOrigin(), { url }, passedTarget, lockHistory, lockBackForwardList, shouldSendReferrer, AllowNavigationToInvalidURL::Yes, newFrameOpenerPolicy, shouldOpenExternalURLsPolicy, initiatedByMainFrame, DoNotReplaceDocumentIfJavaScriptURL, downloadAttribute, systemPreviewInfo), triggeringEvent);
> }
> 
>diff --git a/Source/WebCore/loader/NavigationAction.cpp b/Source/WebCore/loader/NavigationAction.cpp
>index ba157991414528bdfdd460b6e337bedef5df61de..54544d6bb9efc524ad902b1d7ff434d732443047 100644
>--- a/Source/WebCore/loader/NavigationAction.cpp
>+++ b/Source/WebCore/loader/NavigationAction.cpp
>@@ -40,7 +40,7 @@ namespace WebCore {
> NavigationAction::Requester::Requester(const Document& document)
>     : m_url { URL { document.url() } }
>     , m_origin { makeRefPtr(document.securityOrigin()) }
>-    , m_pageIDAndFrameIDPair { document.frame() ? std::make_pair(document.frame()->loader().client().pageID().value_or(0), document.frame()->loader().client().frameID().value_or(0)) : std::make_pair<uint64_t, uint64_t>(0, 0) }
>+    , m_pageIDAndFrameIDPair { document.frame() ? std::make_pair(document.frame()->loader().client().pageID().valueOr(0), document.frame()->loader().client().frameID().valueOr(0)) : std::make_pair<uint64_t, uint64_t>(0, 0) }
> {
> }
> 
>diff --git a/Source/WebCore/page/FrameView.cpp b/Source/WebCore/page/FrameView.cpp
>index 4542f0bf7549562700a6b62c1bcd51f6dde414db..a7e0a5e6008e8c3c7ae6ee1818ed57b093a32c0c 100644
>--- a/Source/WebCore/page/FrameView.cpp
>+++ b/Source/WebCore/page/FrameView.cpp
>@@ -1671,7 +1671,7 @@ void FrameView::setLayoutViewportOverrideRect(Optional<LayoutRect> rect, Trigger
>     if (oldRect.height() != layoutViewportRect().height())
>         layoutTriggering = TriggerLayoutOrNot::Yes;
> 
>-    LOG_WITH_STREAM(Scrolling, stream << "\nFrameView " << this << " setLayoutViewportOverrideRect() - changing override layout viewport from " << oldRect << " to " << m_layoutViewportOverrideRect.value_or(LayoutRect()) << " layoutTriggering " << (layoutTriggering == TriggerLayoutOrNot::Yes ? "yes" : "no"));
>+    LOG_WITH_STREAM(Scrolling, stream << "\nFrameView " << this << " setLayoutViewportOverrideRect() - changing override layout viewport from " << oldRect << " to " << m_layoutViewportOverrideRect.valueOr(LayoutRect()) << " layoutTriggering " << (layoutTriggering == TriggerLayoutOrNot::Yes ? "yes" : "no"));
> 
>     if (oldRect != layoutViewportRect() && layoutTriggering == TriggerLayoutOrNot::Yes)
>         setViewportConstrainedObjectsNeedLayout();
>@@ -4823,7 +4823,7 @@ IntPoint FrameView::convertFromContainingView(const IntPoint& parentPoint) const
> float FrameView::documentToAbsoluteScaleFactor(Optional<float> effectiveZoom) const
> {
>     // If effectiveZoom is passed, it already factors in pageZoomFactor(). 
>-    return effectiveZoom.value_or(frame().pageZoomFactor()) * frame().frameScaleFactor();
>+    return effectiveZoom.valueOr(frame().pageZoomFactor()) * frame().frameScaleFactor();
> }
> 
> float FrameView::absoluteToDocumentScaleFactor(Optional<float> effectiveZoom) const
>@@ -5370,16 +5370,16 @@ IntSize FrameView::viewportSizeForCSSViewportUnits() const
> 
>     if (useFixedLayout()) {
>         auto fixedLayoutSize = this->fixedLayoutSize();
>-        viewportSize.width = viewportSize.width.value_or(fixedLayoutSize.width());
>-        viewportSize.height = viewportSize.height.value_or(fixedLayoutSize.height());
>+        viewportSize.width = viewportSize.width.valueOr(fixedLayoutSize.width());
>+        viewportSize.height = viewportSize.height.valueOr(fixedLayoutSize.height());
>         return { *viewportSize.width, *viewportSize.height };
>     }
>     
>     // FIXME: the value returned should take into account the value of the overflow
>     // property on the root element.
>     auto visibleContentSizeIncludingScrollbars = visibleContentRectIncludingScrollbars().size();
>-    viewportSize.width = viewportSize.width.value_or(visibleContentSizeIncludingScrollbars.width());
>-    viewportSize.height = viewportSize.height.value_or(visibleContentSizeIncludingScrollbars.height());
>+    viewportSize.width = viewportSize.width.valueOr(visibleContentSizeIncludingScrollbars.width());
>+    viewportSize.height = viewportSize.height.valueOr(visibleContentSizeIncludingScrollbars.height());
>     return { *viewportSize.width, *viewportSize.height };
> }
> 
>diff --git a/Source/WebCore/page/Page.cpp b/Source/WebCore/page/Page.cpp
>index e7251ee1a15fe2e1d803fece598e4c3bf2c63ba6..63d6e94862ea9df0fba084f5cb26bd467482d371 100644
>--- a/Source/WebCore/page/Page.cpp
>+++ b/Source/WebCore/page/Page.cpp
>@@ -1128,7 +1128,7 @@ bool Page::isLowPowerModeEnabled() const
> void Page::setLowPowerModeEnabledOverrideForTesting(Optional<bool> isEnabled)
> {
>     m_lowPowerModeEnabledOverrideForTesting = isEnabled;
>-    handleLowModePowerChange(m_lowPowerModeEnabledOverrideForTesting.value_or(false));
>+    handleLowModePowerChange(m_lowPowerModeEnabledOverrideForTesting.valueOr(false));
> }
> 
> void Page::setTopContentInset(float contentInset)
>diff --git a/Source/WebCore/page/SecurityOriginData.cpp b/Source/WebCore/page/SecurityOriginData.cpp
>index 12364424527962b89f4780c51bc6baa3a3704456..05f8b19dae5879d0cdfda7c7649eca2b44c398a6 100644
>--- a/Source/WebCore/page/SecurityOriginData.cpp
>+++ b/Source/WebCore/page/SecurityOriginData.cpp
>@@ -80,7 +80,7 @@ String SecurityOriginData::databaseIdentifier() const
>     stringBuilder.append(separatorCharacter);
>     stringBuilder.append(FileSystem::encodeForFileName(host));
>     stringBuilder.append(separatorCharacter);
>-    stringBuilder.appendNumber(port.value_or(0));
>+    stringBuilder.appendNumber(port.valueOr(0));
>     
>     return stringBuilder.toString();
> }
>diff --git a/Source/WebCore/page/SecurityOriginData.h b/Source/WebCore/page/SecurityOriginData.h
>index 59251022aa28ac50dd8ee2b3669707d0894cc543..244371e20b1adf1ec5ce35b819ead9479633f85b 100644
>--- a/Source/WebCore/page/SecurityOriginData.h
>+++ b/Source/WebCore/page/SecurityOriginData.h
>@@ -134,7 +134,7 @@ struct SecurityOriginDataHash {
>         unsigned hashCodes[3] = {
>             data.protocol.impl() ? data.protocol.impl()->hash() : 0,
>             data.host.impl() ? data.host.impl()->hash() : 0,
>-            data.port.value_or(0)
>+            data.port.valueOr(0)
>         };
>         return StringHasher::hashMemory<sizeof(hashCodes)>(hashCodes);
>     }
>diff --git a/Source/WebCore/page/SecurityOriginHash.h b/Source/WebCore/page/SecurityOriginHash.h
>index e0148a2d05d99b0dddf06a23d246d53452cb2c13..f9a52fa1f413a712d8aee895818f8f351ae93e7a 100644
>--- a/Source/WebCore/page/SecurityOriginHash.h
>+++ b/Source/WebCore/page/SecurityOriginHash.h
>@@ -40,7 +40,7 @@ struct SecurityOriginHash {
>         unsigned hashCodes[3] = {
>             origin->protocol().impl() ? origin->protocol().impl()->hash() : 0,
>             origin->host().impl() ? origin->host().impl()->hash() : 0,
>-            origin->port().value_or(0)
>+            origin->port().valueOr(0)
>         };
>         return StringHasher::hashMemory<sizeof(hashCodes)>(hashCodes);
>     }
>diff --git a/Source/WebCore/page/ViewportConfiguration.cpp b/Source/WebCore/page/ViewportConfiguration.cpp
>index 1d36b8eeb0bec052e6100d0edeb311326326e711..ca9cd96850c7f46bc16349b9205c81e0de87b11c 100644
>--- a/Source/WebCore/page/ViewportConfiguration.cpp
>+++ b/Source/WebCore/page/ViewportConfiguration.cpp
>@@ -116,8 +116,8 @@ bool ViewportConfiguration::setContentsSize(const IntSize& contentSize)
> 
> bool ViewportConfiguration::setViewLayoutSize(const FloatSize& viewLayoutSize, Optional<double>&& scaleFactor, Optional<double>&& minimumEffectiveDeviceWidth)
> {
>-    double newScaleFactor = scaleFactor.value_or(m_layoutSizeScaleFactor);
>-    double newEffectiveWidth = minimumEffectiveDeviceWidth.value_or(m_minimumEffectiveDeviceWidth);
>+    double newScaleFactor = scaleFactor.valueOr(m_layoutSizeScaleFactor);
>+    double newEffectiveWidth = minimumEffectiveDeviceWidth.valueOr(m_minimumEffectiveDeviceWidth);
>     if (m_viewLayoutSize == viewLayoutSize && m_layoutSizeScaleFactor == newScaleFactor && newEffectiveWidth == m_minimumEffectiveDeviceWidth)
>         return false;
> 
>diff --git a/Source/WebCore/page/WindowFeatures.cpp b/Source/WebCore/page/WindowFeatures.cpp
>index 1dbbd56cdfdf6e51ae0b71c6b11cb8e115c94f55..078f897ba9fa602feb61de6158902e88be8f0d12 100644
>--- a/Source/WebCore/page/WindowFeatures.cpp
>+++ b/Source/WebCore/page/WindowFeatures.cpp
>@@ -182,8 +182,8 @@ WindowFeatures parseDialogFeatures(const String& dialogFeaturesString, const Flo
>     features.locationBarVisible = false;
>     features.dialog = true;
> 
>-    float width = floatFeature(featuresMap, "dialogwidth", 100, screenAvailableRect.width()).value_or(620); // default here came from frame size of dialog in MacIE
>-    float height = floatFeature(featuresMap, "dialogheight", 100, screenAvailableRect.height()).value_or(450); // default here came from frame size of dialog in MacIE
>+    float width = floatFeature(featuresMap, "dialogwidth", 100, screenAvailableRect.width()).valueOr(620); // default here came from frame size of dialog in MacIE
>+    float height = floatFeature(featuresMap, "dialogheight", 100, screenAvailableRect.height()).valueOr(450); // default here came from frame size of dialog in MacIE
> 
>     features.width = width;
>     features.height = height;
>@@ -191,16 +191,16 @@ WindowFeatures parseDialogFeatures(const String& dialogFeaturesString, const Flo
>     features.x = floatFeature(featuresMap, "dialogleft", screenAvailableRect.x(), screenAvailableRect.maxX() - width);
>     features.y = floatFeature(featuresMap, "dialogtop", screenAvailableRect.y(), screenAvailableRect.maxY() - height);
> 
>-    if (boolFeature(featuresMap, "center").value_or(true)) {
>+    if (boolFeature(featuresMap, "center").valueOr(true)) {
>         if (!features.x)
>             features.x = screenAvailableRect.x() + (screenAvailableRect.width() - width) / 2;
>         if (!features.y)
>             features.y = screenAvailableRect.y() + (screenAvailableRect.height() - height) / 2;
>     }
> 
>-    features.resizable = boolFeature(featuresMap, "resizable").value_or(false);
>-    features.scrollbarsVisible = boolFeature(featuresMap, "scroll").value_or(true);
>-    features.statusBarVisible = boolFeature(featuresMap, "status").value_or(false);
>+    features.resizable = boolFeature(featuresMap, "resizable").valueOr(false);
>+    features.scrollbarsVisible = boolFeature(featuresMap, "scroll").valueOr(true);
>+    features.statusBarVisible = boolFeature(featuresMap, "status").valueOr(false);
> 
>     return features;
> }
>diff --git a/Source/WebCore/page/animation/AnimationBase.cpp b/Source/WebCore/page/animation/AnimationBase.cpp
>index 90be9840ecc7709d81fe19263bd906f982988bf2..3a74f96934869d33d6c952c12d668ef6306043af 100644
>--- a/Source/WebCore/page/animation/AnimationBase.cpp
>+++ b/Source/WebCore/page/animation/AnimationBase.cpp
>@@ -207,7 +207,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>     if (input == AnimationStateInput::ResumeOverride) {
>         if (m_animationState == AnimationState::Looping || m_animationState == AnimationState::Ending) {
>             // Start the animation
>-            startAnimation(beginAnimationUpdateTime() - m_startTime.value_or(0));
>+            startAnimation(beginAnimationUpdateTime() - m_startTime.valueOr(0));
>         }
>         return;
>     }
>@@ -313,7 +313,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>                 // We are pausing while waiting for a start response. Cancel the animation and wait. When 
>                 // we unpause, we will act as though the start timer just fired
>                 m_pauseTime = beginAnimationUpdateTime();
>-                pauseAnimation(beginAnimationUpdateTime() - m_startTime.value_or(0));
>+                pauseAnimation(beginAnimationUpdateTime() - m_startTime.valueOr(0));
>                 LOG(Animations, "%p AnimationState %s -> PausedWaitResponse", this, nameForState(m_animationState));
>                 m_animationState = AnimationState::PausedWaitResponse;
>             }
>@@ -333,7 +333,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>             } else {
>                 // We are pausing while running. Cancel the animation and wait
>                 m_pauseTime = beginAnimationUpdateTime();
>-                pauseAnimation(beginAnimationUpdateTime() - m_startTime.value_or(0));
>+                pauseAnimation(beginAnimationUpdateTime() - m_startTime.valueOr(0));
>                 LOG(Animations, "%p AnimationState %s -> PausedRun", this, nameForState(m_animationState));
>                 m_animationState = AnimationState::PausedRun;
>             }
>@@ -365,7 +365,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>             } else {
>                 // We are pausing while running. Cancel the animation and wait
>                 m_pauseTime = beginAnimationUpdateTime();
>-                pauseAnimation(beginAnimationUpdateTime() - m_startTime.value_or(0));
>+                pauseAnimation(beginAnimationUpdateTime() - m_startTime.valueOr(0));
>                 LOG(Animations, "%p AnimationState %s -> PausedRun", this, nameForState(m_animationState));
>                 m_animationState = AnimationState::PausedRun;
>             }
>@@ -375,7 +375,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>             ASSERT(input == AnimationStateInput::PlayStateRunning);
>             ASSERT(paused());
>             // Update the times
>-            m_startTime = m_startTime.value_or(0) + beginAnimationUpdateTime() - m_pauseTime.value_or(0);
>+            m_startTime = m_startTime.valueOr(0) + beginAnimationUpdateTime() - m_pauseTime.valueOr(0);
>             m_pauseTime = WTF::nullopt;
> 
>             // we were waiting for the start timer to fire, go back and wait again
>@@ -407,7 +407,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
> 
>                 // Update the times
>                 if (m_animationState == AnimationState::PausedRun)
>-                    m_startTime = m_startTime.value_or(0) + beginAnimationUpdateTime() - m_pauseTime.value_or(0);
>+                    m_startTime = m_startTime.valueOr(0) + beginAnimationUpdateTime() - m_pauseTime.valueOr(0);
>                 else
>                     m_startTime = 0;
> 
>@@ -430,7 +430,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>                         updateStateMachine(AnimationStateInput::StartTimeSet, beginAnimationUpdateTime());
>                         m_isAccelerated = true;
>                     } else {
>-                        bool started = startAnimation(beginAnimationUpdateTime() - m_startTime.value_or(0));
>+                        bool started = startAnimation(beginAnimationUpdateTime() - m_startTime.valueOr(0));
>                         m_compositeAnimation->animationController().addToAnimationsWaitingForStartTimeResponse(this, started);
>                         m_isAccelerated = started;
>                     }
>@@ -447,7 +447,7 @@ void AnimationBase::updateStateMachine(AnimationStateInput input, double param)
>                 m_animationState = AnimationState::PausedRun;
>                 ASSERT(!m_startTime);
>                 m_startTime = param;
>-                m_pauseTime = m_pauseTime.value_or(0) + param;
>+                m_pauseTime = m_pauseTime.valueOr(0) + param;
>                 break;
>             }
> 
>@@ -494,7 +494,7 @@ void AnimationBase::fireAnimationEventsIfNeeded()
>         return;
>     }
> 
>-    double elapsedDuration = beginAnimationUpdateTime() - m_startTime.value_or(0);
>+    double elapsedDuration = beginAnimationUpdateTime() - m_startTime.valueOr(0);
> 
>     // FIXME: we need to ensure that elapsedDuration is never < 0. If it is, this suggests that
>     // we had a recalcStyle() outside of beginAnimationUpdate()/endAnimationUpdate().
>@@ -631,9 +631,9 @@ double AnimationBase::progress(double scale, double offset, const TimingFunction
> void AnimationBase::getTimeToNextEvent(Seconds& time, bool& isLooping) const
> {
>     // Decide when the end or loop event needs to fire
>-    const double elapsedDuration = std::max(beginAnimationUpdateTime() - m_startTime.value_or(0), 0.0);
>+    const double elapsedDuration = std::max(beginAnimationUpdateTime() - m_startTime.valueOr(0), 0.0);
>     double durationLeft = 0;
>-    double nextIterationTime = m_totalDuration.value_or(0);
>+    double nextIterationTime = m_totalDuration.valueOr(0);
> 
>     if (!m_totalDuration || elapsedDuration < m_totalDuration.value()) {
>         durationLeft = m_animation->duration() > 0 ? (m_animation->duration() - fmod(elapsedDuration, m_animation->duration())) : 0;
>@@ -675,9 +675,9 @@ void AnimationBase::freezeAtTime(double t)
> 
>     ASSERT(m_startTime); // If m_startTime is zero, we haven't started yet, so we'll get a bad pause time.
>     if (t <= m_animation->delay())
>-        m_pauseTime = m_startTime.value_or(0);
>+        m_pauseTime = m_startTime.valueOr(0);
>     else
>-        m_pauseTime = m_startTime.value_or(0) + t - m_animation->delay();
>+        m_pauseTime = m_startTime.valueOr(0) + t - m_animation->delay();
> 
>     if (auto* renderer = compositedRenderer())
>         renderer->suspendAnimations(MonotonicTime::fromRawSeconds(m_pauseTime.value()));
>@@ -695,16 +695,16 @@ double AnimationBase::getElapsedTime() const
> {
>     if (paused()) {
>         double delayOffset = (!m_startTime && m_animation->delay() < 0) ? m_animation->delay() : 0;
>-        return m_pauseTime.value_or(0) - m_startTime.value_or(0) - delayOffset;
>+        return m_pauseTime.valueOr(0) - m_startTime.valueOr(0) - delayOffset;
>     }
> 
>     if (!m_startTime)
>         return 0;
> 
>     if (postActive() || fillingForwards())
>-        return m_totalDuration.value_or(0);
>+        return m_totalDuration.valueOr(0);
> 
>-    return beginAnimationUpdateTime() - m_startTime.value_or(0);
>+    return beginAnimationUpdateTime() - m_startTime.valueOr(0);
> }
> 
> void AnimationBase::setElapsedTime(double time)
>diff --git a/Source/WebCore/page/animation/CSSAnimationController.cpp b/Source/WebCore/page/animation/CSSAnimationController.cpp
>index 250e6d68028eef91811225e3956b8f9fcbc644e8..dc1ceab3ab2094a4a627f563df98757eb60104a3 100644
>--- a/Source/WebCore/page/animation/CSSAnimationController.cpp
>+++ b/Source/WebCore/page/animation/CSSAnimationController.cpp
>@@ -178,7 +178,7 @@ void CSSAnimationControllerPrivate::updateAnimationTimer(SetChanged callSetChang
> {
>     Optional<Seconds> timeToNextService = updateAnimations(callSetChanged);
> 
>-    LOG(Animations, "updateAnimationTimer: timeToNextService is %.2f", timeToNextService.value_or(Seconds { -1 }).value());
>+    LOG(Animations, "updateAnimationTimer: timeToNextService is %.2f", timeToNextService.valueOr(Seconds { -1 }).value());
> 
>     // If we don't need service, we want to make sure the timer is no longer running
>     if (!timeToNextService) {
>diff --git a/Source/WebCore/page/cocoa/ResourceUsageThreadCocoa.mm b/Source/WebCore/page/cocoa/ResourceUsageThreadCocoa.mm
>index efd836afd68d32394fe54727449d68db9f43d486..698fb8de64deb11f43dca5b31999a4ea1bedb348 100644
>--- a/Source/WebCore/page/cocoa/ResourceUsageThreadCocoa.mm
>+++ b/Source/WebCore/page/cocoa/ResourceUsageThreadCocoa.mm
>@@ -249,8 +249,8 @@ void ResourceUsageThread::platformThreadBody(JSC::VM* vm, ResourceUsageData& dat
>     data.totalExternalSize = currentGCOwnedExternal;
> 
>     auto now = MonotonicTime::now();
>-    data.timeOfNextEdenCollection = now + vm->heap.edenActivityCallback()->timeUntilFire().value_or(Seconds(std::numeric_limits<double>::infinity()));
>-    data.timeOfNextFullCollection = now + vm->heap.fullActivityCallback()->timeUntilFire().value_or(Seconds(std::numeric_limits<double>::infinity()));
>+    data.timeOfNextEdenCollection = now + vm->heap.edenActivityCallback()->timeUntilFire().valueOr(Seconds(std::numeric_limits<double>::infinity()));
>+    data.timeOfNextFullCollection = now + vm->heap.fullActivityCallback()->timeUntilFire().valueOr(Seconds(std::numeric_limits<double>::infinity()));
> }
> 
> }
>diff --git a/Source/WebCore/page/linux/ResourceUsageThreadLinux.cpp b/Source/WebCore/page/linux/ResourceUsageThreadLinux.cpp
>index dcafb6f8affedb94b58a7639fc03a346506414a5..1562a08c57991dedae71066f0cfec39c81984e64 100644
>--- a/Source/WebCore/page/linux/ResourceUsageThreadLinux.cpp
>+++ b/Source/WebCore/page/linux/ResourceUsageThreadLinux.cpp
>@@ -170,8 +170,8 @@ void ResourceUsageThread::platformThreadBody(JSC::VM* vm, ResourceUsageData& dat
>     data.totalExternalSize = currentGCOwnedExternal;
> 
>     auto now = MonotonicTime::now();
>-    data.timeOfNextEdenCollection = now + vm->heap.edenActivityCallback()->timeUntilFire().value_or(Seconds(std::numeric_limits<double>::infinity()));
>-    data.timeOfNextFullCollection = now + vm->heap.fullActivityCallback()->timeUntilFire().value_or(Seconds(std::numeric_limits<double>::infinity()));
>+    data.timeOfNextEdenCollection = now + vm->heap.edenActivityCallback()->timeUntilFire().valueOr(Seconds(std::numeric_limits<double>::infinity()));
>+    data.timeOfNextFullCollection = now + vm->heap.fullActivityCallback()->timeUntilFire().valueOr(Seconds(std::numeric_limits<double>::infinity()));
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/platform/graphics/ComplexTextController.cpp b/Source/WebCore/platform/graphics/ComplexTextController.cpp
>index f479f9bec9ce3d62617b739ac5a78d52e60e88df..9a9c97686126f31c4dca92ec3a9935904ec55378 100644
>--- a/Source/WebCore/platform/graphics/ComplexTextController.cpp
>+++ b/Source/WebCore/platform/graphics/ComplexTextController.cpp
>@@ -222,12 +222,12 @@ unsigned ComplexTextController::offsetForPosition(float h, bool includePartialGl
>                 if (cursorPositionIterator.isBoundary(hitIndex))
>                     clusterStart = hitIndex;
>                 else
>-                    clusterStart = cursorPositionIterator.preceding(hitIndex).value_or(0);
>+                    clusterStart = cursorPositionIterator.preceding(hitIndex).valueOr(0);
> 
>                 if (!includePartialGlyphs)
>                     return complexTextRun.stringLocation() + clusterStart;
> 
>-                unsigned clusterEnd = cursorPositionIterator.following(hitIndex).value_or(stringLength);
>+                unsigned clusterEnd = cursorPositionIterator.following(hitIndex).valueOr(stringLength);
> 
>                 float clusterWidth;
>                 // FIXME: The search stops at the boundaries of complexTextRun. In theory, it should go on into neighboring ComplexTextRuns
>diff --git a/Source/WebCore/platform/graphics/FontCache.h b/Source/WebCore/platform/graphics/FontCache.h
>index d40d3b9b23d7502bf16e240a60f4c310b28c16fd..b635a13cc48840f08e371f7c882cedbe00215a66 100644
>--- a/Source/WebCore/platform/graphics/FontCache.h
>+++ b/Source/WebCore/platform/graphics/FontCache.h
>@@ -113,7 +113,7 @@ struct FontDescriptionKey {
>         hasher.add(m_size);
>         hasher.add(m_fontSelectionRequest.weight);
>         hasher.add(m_fontSelectionRequest.width);
>-        hasher.add(m_fontSelectionRequest.slope.value_or(normalItalicValue()));
>+        hasher.add(m_fontSelectionRequest.slope.valueOr(normalItalicValue()));
>         hasher.add(m_locale.existingHash());
>         for (unsigned flagItem : m_flags)
>             hasher.add(flagItem);
>diff --git a/Source/WebCore/platform/graphics/FontCascade.cpp b/Source/WebCore/platform/graphics/FontCascade.cpp
>index 3432dca62ed92d064de259230f8630886f1c7ec8..b3b64681fc466ba69dcc63d4e96c450414e310bc 100644
>--- a/Source/WebCore/platform/graphics/FontCascade.cpp
>+++ b/Source/WebCore/platform/graphics/FontCascade.cpp
>@@ -286,7 +286,7 @@ float FontCascade::glyphBufferForTextRun(CodePath codePathToUse, const TextRun&
> 
> float FontCascade::drawText(GraphicsContext& context, const TextRun& run, const FloatPoint& point, unsigned from, Optional<unsigned> to, CustomFontNotReadyAction customFontNotReadyAction) const
> {
>-    unsigned destination = to.value_or(run.length());
>+    unsigned destination = to.valueOr(run.length());
>     GlyphBuffer glyphBuffer;
>     float startX = point.x() + glyphBufferForTextRun(codePath(run, from, to), run, from, destination, glyphBuffer);
>     // We couldn't generate any glyphs for the run. Give up.
>@@ -303,7 +303,7 @@ void FontCascade::drawEmphasisMarks(GraphicsContext& context, const TextRun& run
>     if (isLoadingCustomFonts())
>         return;
> 
>-    unsigned destination = to.value_or(run.length());
>+    unsigned destination = to.valueOr(run.length());
>     if (codePath(run, from, to) != Complex)
>         drawEmphasisMarksForSimpleText(context, run, mark, point, from, destination);
>     else
>@@ -313,7 +313,7 @@ void FontCascade::drawEmphasisMarks(GraphicsContext& context, const TextRun& run
> std::unique_ptr<DisplayList::DisplayList> FontCascade::displayListForTextRun(GraphicsContext& context, const TextRun& run, unsigned from, Optional<unsigned> to, CustomFontNotReadyAction customFontNotReadyAction) const
> {
>     ASSERT(!context.paintingDisabled());
>-    unsigned destination = to.value_or(run.length());
>+    unsigned destination = to.valueOr(run.length());
>     
>     // FIXME: Use the fast code path once it handles partial runs with kerning and ligatures. See http://webkit.org/b/100050
>     CodePath codePathToUse = codePath(run);
>@@ -545,7 +545,7 @@ bool FontCascade::fastAverageCharWidthIfAvailable(float& width) const
> 
> void FontCascade::adjustSelectionRectForText(const TextRun& run, LayoutRect& selectionRect, unsigned from, Optional<unsigned> to) const
> {
>-    unsigned destination = to.value_or(run.length());
>+    unsigned destination = to.valueOr(run.length());
>     if (codePath(run, from, to) != Complex)
>         return adjustSelectionRectForSimpleText(run, selectionRect, from, destination);
> 
>@@ -619,7 +619,7 @@ FontCascade::CodePath FontCascade::codePath(const TextRun& run, Optional<unsigne
> 
> #if !USE(FREETYPE)
>     // FIXME: Use the fast code path once it handles partial runs with kerning and ligatures. See http://webkit.org/b/100050
>-    if ((enableKerning() || requiresShaping()) && (from.value_or(0) || to.value_or(run.length()) != run.length()))
>+    if ((enableKerning() || requiresShaping()) && (from.valueOr(0) || to.valueOr(run.length()) != run.length()))
>         return Complex;
> #else
>     UNUSED_PARAM(from);
>diff --git a/Source/WebCore/platform/graphics/FontSelectionAlgorithm.cpp b/Source/WebCore/platform/graphics/FontSelectionAlgorithm.cpp
>index 357b4023ee08da0cde89682d8dcc778e1c8efe03..6e5f8b49b7c4a4a74b89ee40643f1c8bd12d256c 100644
>--- a/Source/WebCore/platform/graphics/FontSelectionAlgorithm.cpp
>+++ b/Source/WebCore/platform/graphics/FontSelectionAlgorithm.cpp
>@@ -66,7 +66,7 @@ auto FontSelectionAlgorithm::stretchDistance(Capabilities capabilities) const ->
> auto FontSelectionAlgorithm::styleDistance(Capabilities capabilities) const -> DistanceResult
> {
>     auto slope = capabilities.slope;
>-    auto requestSlope = m_request.slope.value_or(normalItalicValue());
>+    auto requestSlope = m_request.slope.valueOr(normalItalicValue());
>     ASSERT(slope.isValid());
>     if (slope.includes(requestSlope))
>         return { FontSelectionValue(), requestSlope };
>diff --git a/Source/WebCore/platform/graphics/FontSelectionAlgorithm.h b/Source/WebCore/platform/graphics/FontSelectionAlgorithm.h
>index ab47057a14c1779e58fb9720e39ad38a1b74d7ec..6b11b9a3188ec5a49d52091ae713bd1d5f248bd7 100644
>--- a/Source/WebCore/platform/graphics/FontSelectionAlgorithm.h
>+++ b/Source/WebCore/platform/graphics/FontSelectionAlgorithm.h
>@@ -353,7 +353,7 @@ inline TextStream& operator<<(TextStream& ts, const FontSelectionValue& fontSele
> 
> inline TextStream& operator<<(TextStream& ts, const Optional<FontSelectionValue>& optionalFontSelectionValue)
> {
>-    ts << optionalFontSelectionValue.value_or(normalItalicValue());
>+    ts << optionalFontSelectionValue.valueOr(normalItalicValue());
>     return ts;
> }
> 
>@@ -432,17 +432,17 @@ struct FontSelectionSpecifiedCapabilities {
> 
>     constexpr Range computeWeight() const
>     {
>-        return weight.value_or(Range { normalWeightValue() });
>+        return weight.valueOr(Range { normalWeightValue() });
>     }
> 
>     constexpr Range computeWidth() const
>     {
>-        return width.value_or(Range { normalStretchValue() });
>+        return width.valueOr(Range { normalStretchValue() });
>     }
> 
>     constexpr Range computeSlope() const
>     {
>-        return slope.value_or(Range { normalItalicValue() });
>+        return slope.valueOr(Range { normalItalicValue() });
>     }
> 
>     OptionalRange weight;
>diff --git a/Source/WebCore/platform/graphics/ShadowBlur.cpp b/Source/WebCore/platform/graphics/ShadowBlur.cpp
>index fe049a4b8e6703d61bc1adb5006885fcc7ed3fa5..fdc2b78bc65b0fb629a564c103d1984cd2865d4c 100644
>--- a/Source/WebCore/platform/graphics/ShadowBlur.cpp
>+++ b/Source/WebCore/platform/graphics/ShadowBlur.cpp
>@@ -390,7 +390,7 @@ IntSize ShadowBlur::calculateLayerBoundingRect(const AffineTransform& transform,
>     if (m_shadowsIgnoreTransforms && !transform.isIdentity()) {
>         FloatQuad transformedPolygon = transform.mapQuad(FloatQuad(shadowedRect));
>         transformedPolygon.move(m_offset);
>-        layerRect = transform.inverse().value_or(AffineTransform()).mapQuad(transformedPolygon).boundingBox();
>+        layerRect = transform.inverse().valueOr(AffineTransform()).mapQuad(transformedPolygon).boundingBox();
>     } else {
>         layerRect = shadowedRect;
>         layerRect.move(m_offset);
>diff --git a/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm b/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm
>index 7b935bf1b326658567c82e7aa4e9b9cff6692c20..cf7dc0c4d896b5590c210f29dbf8e1c16959c106 100644
>--- a/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm
>+++ b/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm
>@@ -2350,7 +2350,7 @@ void MediaPlayerPrivateAVFoundationObjC::paintWithVideoOutput(GraphicsContext& c
>     GraphicsContextStateSaver stateSaver(context);
>     FloatRect imageRect(0, 0, CGImageGetWidth(m_lastImage.get()), CGImageGetHeight(m_lastImage.get()));
>     AffineTransform videoTransform = [firstEnabledVideoTrack preferredTransform];
>-    FloatRect transformedOutputRect = videoTransform.inverse().value_or(AffineTransform()).mapRect(outputRect);
>+    FloatRect transformedOutputRect = videoTransform.inverse().valueOr(AffineTransform()).mapRect(outputRect);
> 
>     context.concatCTM(videoTransform);
>     context.drawNativeImage(m_lastImage.get(), imageRect.size(), transformedOutputRect, imageRect);
>diff --git a/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateMediaStreamAVFObjC.mm b/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateMediaStreamAVFObjC.mm
>index 1b07b4eb80240ed6d50d0773b8763d44dab97d5f..238a2ea3958c31b66bfd4867ddaad8a585d9a539 100644
>--- a/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateMediaStreamAVFObjC.mm
>+++ b/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateMediaStreamAVFObjC.mm
>@@ -1119,7 +1119,7 @@ void MediaPlayerPrivateMediaStreamAVFObjC::paintCurrentFrameInContext(GraphicsCo
>     auto image = m_imagePainter.cgImage.get();
>     FloatRect imageRect(0, 0, CGImageGetWidth(image), CGImageGetHeight(image));
>     AffineTransform videoTransform = videoTransformationMatrix(*m_imagePainter.mediaSample);
>-    FloatRect transformedDestRect = videoTransform.inverse().value_or(AffineTransform()).mapRect(destRect);
>+    FloatRect transformedDestRect = videoTransform.inverse().valueOr(AffineTransform()).mapRect(destRect);
>     context.concatCTM(videoTransform);
>     context.drawNativeImage(image, imageRect.size(), transformedDestRect, imageRect);
> }
>diff --git a/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm b/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm
>index a2e07cf6f3217b3adf895c92b0239494294585c1..65cfb24ae400686ef07080d5409fedf87c2f1f7a 100644
>--- a/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm
>+++ b/Source/WebCore/platform/graphics/avfoundation/objc/SourceBufferPrivateAVFObjC.mm
>@@ -1173,7 +1173,7 @@ void SourceBufferPrivateAVFObjC::willSeek()
> 
> FloatSize SourceBufferPrivateAVFObjC::naturalSize()
> {
>-    return m_cachedSize.value_or(FloatSize());
>+    return m_cachedSize.valueOr(FloatSize());
> }
> 
> void SourceBufferPrivateAVFObjC::didBecomeReadyForMoreSamples(int trackID)
>diff --git a/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp b/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp
>index 6a5152962a6465e64fe9c05814e6e235e11e26af..650eb6c8e54ab7225ea8940c1d8213becdb0fd95 100644
>--- a/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp
>+++ b/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp
>@@ -1462,7 +1462,7 @@ void GraphicsLayerCA::setVisibleAndCoverageRects(const VisibleAndCoverageRects&
>     auto bounds = FloatRect(m_boundsOrigin, size());
>     if (auto extent = animationExtent()) {
>         // Adjust the animation extent to match the current animation position.
>-        bounds = rects.animatingTransform.inverse().value_or(TransformationMatrix()).mapRect(*extent);
>+        bounds = rects.animatingTransform.inverse().valueOr(TransformationMatrix()).mapRect(*extent);
>     }
> 
>     // FIXME: we need to take reflections into account when determining whether this layer intersects the coverage rect.
>diff --git a/Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp b/Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp
>index 50bdb5f5f25a67b36fcce32c5a4c657a67bc3be8..e258141e99ad28a5414c6a45de83b279e47796c5 100644
>--- a/Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp
>+++ b/Source/WebCore/platform/graphics/cocoa/FontCacheCoreText.cpp
>@@ -598,7 +598,7 @@ RetainPtr<CTFontRef> preparePlatformFont(CTFontRef originalFont, const FontDescr
>     if (applyWeightWidthSlopeVariations && !fontIsSystemFont(originalFont)) {
>         float weight = fontSelectionRequest.weight;
>         float width = fontSelectionRequest.width;
>-        float slope = fontSelectionRequest.slope.value_or(normalItalicValue());
>+        float slope = fontSelectionRequest.slope.valueOr(normalItalicValue());
>         if (auto weightValue = fontFaceCapabilities.weight)
>             weight = std::max(std::min(weight, static_cast<float>(weightValue->maximum)), static_cast<float>(weightValue->minimum));
>         if (auto widthValue = fontFaceCapabilities.width)
>diff --git a/Source/WebCore/platform/graphics/filters/FETurbulence.cpp b/Source/WebCore/platform/graphics/filters/FETurbulence.cpp
>index 4d0ded4e4bb4e102e0f54dfd035fe9d4ac59faba..8227879f5786de63505436f1b48017c0add28ef6 100644
>--- a/Source/WebCore/platform/graphics/filters/FETurbulence.cpp
>+++ b/Source/WebCore/platform/graphics/filters/FETurbulence.cpp
>@@ -373,7 +373,7 @@ void FETurbulence::fillRegion(Uint8ClampedArray& pixelArray, const PaintingData&
>     filterRegion.scale(filter().filterScale());
>     FloatPoint point(0, filterRegion.y() + startY);
>     int indexOfPixelChannel = startY * (filterRegion.width() << 2);
>-    AffineTransform inverseTransfrom = filter().absoluteTransform().inverse().value_or(AffineTransform());
>+    AffineTransform inverseTransfrom = filter().absoluteTransform().inverse().valueOr(AffineTransform());
> 
>     for (int y = startY; y < endY; ++y) {
>         point.setY(point.y() + 1);
>diff --git a/Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.cpp b/Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.cpp
>index 1fe8b881e199806b122da56f70f80c35eaacd62a..0ba4739a1de5d42168feed7a05b8682d6057a8b1 100644
>--- a/Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.cpp
>+++ b/Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.cpp
>@@ -223,7 +223,7 @@ bool initializeGStreamer(Optional<Vector<String>>&& options)
>         isGStreamerInitialized = false;
> 
> #if ENABLE(VIDEO) || ENABLE(WEB_AUDIO)
>-        Vector<String> parameters = options.value_or(extractGStreamerOptionsFromCommandLine());
>+        Vector<String> parameters = options.valueOr(extractGStreamerOptionsFromCommandLine());
>         char** argv = g_new0(char*, parameters.size() + 2);
>         int argc = parameters.size() + 1;
>         argv[0] = g_strdup(getCurrentExecutableName().data());
>diff --git a/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp b/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp
>index 196297bd85cd43680d0ed26bc11954312e8039ac..890da9d62b34f77ceb3b047608658efd04d84974 100644
>--- a/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp
>+++ b/Source/WebCore/platform/graphics/texmap/TextureMapperLayer.cpp
>@@ -236,7 +236,7 @@ void TextureMapperLayer::paintSelfAndChildrenWithReplica(const TextureMapperPain
>         TextureMapperPaintOptions replicaOptions(options);
>         replicaOptions.transform
>             .multiply(m_state.replicaLayer->m_layerTransforms.combined)
>-            .multiply(m_layerTransforms.combined.inverse().value_or(TransformationMatrix()));
>+            .multiply(m_layerTransforms.combined.inverse().valueOr(TransformationMatrix()));
>         paintSelfAndChildren(replicaOptions);
>     }
> 
>@@ -246,7 +246,7 @@ void TextureMapperLayer::paintSelfAndChildrenWithReplica(const TextureMapperPain
> TransformationMatrix TextureMapperLayer::replicaTransform()
> {
>     return TransformationMatrix(m_state.replicaLayer->m_layerTransforms.combined)
>-        .multiply(m_layerTransforms.combined.inverse().value_or(TransformationMatrix()));
>+        .multiply(m_layerTransforms.combined.inverse().valueOr(TransformationMatrix()));
> }
> 
> static void resolveOverlaps(Region& newRegion, Region& overlapRegion, Region& nonOverlapRegion)
>@@ -647,9 +647,9 @@ bool TextureMapperLayer::syncAnimations(MonotonicTime time)
>     TextureMapperAnimation::ApplicationResult applicationResults;
>     m_animations.apply(applicationResults, time);
> 
>-    m_layerTransforms.localTransform = applicationResults.transform.value_or(m_state.transform);
>-    m_currentOpacity = applicationResults.opacity.value_or(m_state.opacity);
>-    m_currentFilters = applicationResults.filters.value_or(m_state.filters);
>+    m_layerTransforms.localTransform = applicationResults.transform.valueOr(m_state.transform);
>+    m_currentOpacity = applicationResults.opacity.valueOr(m_state.opacity);
>+    m_currentFilters = applicationResults.filters.valueOr(m_state.filters);
> 
>     return applicationResults.hasRunningAnimations;
> }
>diff --git a/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp b/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp
>index 15ae46f60d7264e1ab57c581938a5b465be3ecff..45ff95156eb4c3e685ade5a912a5cdefbaae6e04 100644
>--- a/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp
>+++ b/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsLayer.cpp
>@@ -825,7 +825,7 @@ IntRect CoordinatedGraphicsLayer::transformedVisibleRect()
>     // Return a projection of the visible rect (surface coordinates) onto the layer's plane (layer coordinates).
>     // The resulting quad might be squewed and the visible rect is the bounding box of this quad,
>     // so it might spread further than the real visible area (and then even more amplified by the cover rect multiplier).
>-    ASSERT(m_cachedInverseTransform == m_layerTransform.combined().inverse().value_or(TransformationMatrix()));
>+    ASSERT(m_cachedInverseTransform == m_layerTransform.combined().inverse().valueOr(TransformationMatrix()));
>     FloatRect rect = m_cachedInverseTransform.clampedBoundsOfProjectedQuad(FloatQuad(m_coordinator->visibleContentsRect()));
>     clampToContentsRectIfRectIsInfinite(rect, size());
>     return enclosingIntRect(rect);
>@@ -1089,7 +1089,7 @@ void CoordinatedGraphicsLayer::computeTransformedVisibleRect()
>     m_layerTransform.setChildrenTransform(childrenTransform());
>     m_layerTransform.combineTransforms(parent() ? downcast<CoordinatedGraphicsLayer>(*parent()).m_layerTransform.combinedForChildren() : TransformationMatrix());
> 
>-    m_cachedInverseTransform = m_layerTransform.combined().inverse().value_or(TransformationMatrix());
>+    m_cachedInverseTransform = m_layerTransform.combined().inverse().valueOr(TransformationMatrix());
> 
>     // The combined transform will be used in tiledBackingStoreVisibleRect.
>     setNeedsVisibleRectAdjustment();
>diff --git a/Source/WebCore/platform/graphics/transforms/TransformState.cpp b/Source/WebCore/platform/graphics/transforms/TransformState.cpp
>index f0e2da3193c4e89911ff7fcb6db8ea84648790e7..e763cc1393dbcde61132118ffb43191c648e45e4 100644
>--- a/Source/WebCore/platform/graphics/transforms/TransformState.cpp
>+++ b/Source/WebCore/platform/graphics/transforms/TransformState.cpp
>@@ -170,7 +170,7 @@ FloatPoint TransformState::mappedPoint(bool* wasClamped) const
>     if (m_direction == ApplyTransformDirection)
>         return m_accumulatedTransform->mapPoint(point);
> 
>-    return m_accumulatedTransform->inverse().value_or(TransformationMatrix()).projectPoint(point, wasClamped);
>+    return m_accumulatedTransform->inverse().valueOr(TransformationMatrix()).projectPoint(point, wasClamped);
> }
> 
> FloatQuad TransformState::mappedQuad(bool* wasClamped) const
>@@ -218,7 +218,7 @@ void TransformState::mapQuad(FloatQuad& quad, TransformDirection direction, bool
>     if (direction == ApplyTransformDirection)
>         quad = m_accumulatedTransform->mapQuad(quad);
> 
>-    quad = m_accumulatedTransform->inverse().value_or(TransformationMatrix()).projectQuad(quad, wasClamped);
>+    quad = m_accumulatedTransform->inverse().valueOr(TransformationMatrix()).projectQuad(quad, wasClamped);
> }
> 
> void TransformState::flattenWithTransform(const TransformationMatrix& t, bool* wasClamped)
>@@ -233,7 +233,7 @@ void TransformState::flattenWithTransform(const TransformationMatrix& t, bool* w
>         }
> 
>     } else {
>-        TransformationMatrix inverseTransform = t.inverse().value_or(TransformationMatrix());
>+        TransformationMatrix inverseTransform = t.inverse().valueOr(TransformationMatrix());
>         if (m_mapPoint)
>             m_lastPlanarPoint = inverseTransform.projectPoint(m_lastPlanarPoint);
>         if (m_mapQuad) {
>diff --git a/Source/WebCore/platform/network/CacheValidation.cpp b/Source/WebCore/platform/network/CacheValidation.cpp
>index 0212bc9f1c7e311b616534de13ec90142489ed59..ef25e9f7178e3683b3bc24775c90a02881d4c62e 100644
>--- a/Source/WebCore/platform/network/CacheValidation.cpp
>+++ b/Source/WebCore/platform/network/CacheValidation.cpp
>@@ -103,7 +103,7 @@ Seconds computeCurrentAge(const ResourceResponse& response, WallTime responseTim
>     // No compensation for latency as that is not terribly important in practice.
>     auto dateValue = response.date();
>     auto apparentAge = dateValue ? std::max(0_us, responseTime - *dateValue) : 0_us;
>-    auto ageValue = response.age().value_or(0_us);
>+    auto ageValue = response.age().valueOr(0_us);
>     auto correctedInitialAge = std::max(apparentAge, ageValue);
>     auto residentTime = WallTime::now() - responseTime;
>     return correctedInitialAge + residentTime;
>@@ -121,7 +121,7 @@ Seconds computeFreshnessLifetimeForHTTPFamily(const ResourceResponse& response,
>         return *maxAge;
> 
>     auto date = response.date();
>-    auto effectiveDate = date.value_or(responseTime);
>+    auto effectiveDate = date.valueOr(responseTime);
>     if (auto expires = response.expires())
>         return *expires - effectiveDate;
> 
>diff --git a/Source/WebCore/platform/network/NetworkStateNotifier.cpp b/Source/WebCore/platform/network/NetworkStateNotifier.cpp
>index b9673de9841293b474a9da4fbc1589f0dc8c7ff2..822e8b06ed42482b616eeee0c225df5d4f74c9cb 100644
>--- a/Source/WebCore/platform/network/NetworkStateNotifier.cpp
>+++ b/Source/WebCore/platform/network/NetworkStateNotifier.cpp
>@@ -50,7 +50,7 @@ bool NetworkStateNotifier::onLine()
> {
>     if (!m_isOnLine)
>         updateState();
>-    return m_isOnLine.value_or(true);
>+    return m_isOnLine.valueOr(true);
> }
> 
> void NetworkStateNotifier::addListener(WTF::Function<void(bool)>&& listener)
>diff --git a/Source/WebCore/rendering/FloatingObjects.cpp b/Source/WebCore/rendering/FloatingObjects.cpp
>index de28d67dd4b382083fccb543ce70db78f7797e52..35ec17c18b900d573c97776f9720e46f654c90b3 100644
>--- a/Source/WebCore/rendering/FloatingObjects.cpp
>+++ b/Source/WebCore/rendering/FloatingObjects.cpp
>@@ -195,8 +195,8 @@ public:
>     LayoutUnit highValue() const { return LayoutUnit::max(); }
>     void collectIfNeeded(const IntervalType&);
> 
>-    LayoutUnit nextLogicalBottom() const { return m_nextLogicalBottom.value_or(0); }
>-    LayoutUnit nextShapeLogicalBottom() const { return m_nextShapeLogicalBottom.value_or(nextLogicalBottom()); }
>+    LayoutUnit nextLogicalBottom() const { return m_nextLogicalBottom.valueOr(0); }
>+    LayoutUnit nextShapeLogicalBottom() const { return m_nextShapeLogicalBottom.valueOr(nextLogicalBottom()); }
> 
> private:
>     WeakPtr<const RenderBlockFlow> m_renderer;
>diff --git a/Source/WebCore/rendering/GridBaselineAlignment.cpp b/Source/WebCore/rendering/GridBaselineAlignment.cpp
>index 1dbb3a4a1d30086f10c6cc6dffde9bc812143ed9..290faca049dcb63dca0eaf490ff7766b1eb82845 100644
>--- a/Source/WebCore/rendering/GridBaselineAlignment.cpp
>+++ b/Source/WebCore/rendering/GridBaselineAlignment.cpp
>@@ -64,7 +64,7 @@ LayoutUnit GridBaselineAlignment::logicalAscentForChild(const RenderBox& child,
> LayoutUnit GridBaselineAlignment::ascentForChild(const RenderBox& child, GridAxis baselineAxis) const
> {
>     LayoutUnit margin = isDescentBaselineForChild(child, baselineAxis) ? marginUnderForChild(child, baselineAxis) : marginOverForChild(child, baselineAxis);
>-    LayoutUnit baseline(isParallelToBaselineAxisForChild(child, baselineAxis) ? child.firstLineBaseline().value_or(-1) : -1);
>+    LayoutUnit baseline(isParallelToBaselineAxisForChild(child, baselineAxis) ? child.firstLineBaseline().valueOr(-1) : -1);
>     // We take border-box's under edge if no valid baseline.
>     if (baseline == -1) {
>         if (isHorizontalBaselineAxis(baselineAxis))
>diff --git a/Source/WebCore/rendering/GridTrackSizingAlgorithm.cpp b/Source/WebCore/rendering/GridTrackSizingAlgorithm.cpp
>index f75376b390baa37ed29fe4052a7babfee2a4f2a6..88c4f5957bccd88f2a028a11e410be2e2820681f 100644
>--- a/Source/WebCore/rendering/GridTrackSizingAlgorithm.cpp
>+++ b/Source/WebCore/rendering/GridTrackSizingAlgorithm.cpp
>@@ -54,7 +54,7 @@ void GridTrack::setBaseSize(LayoutUnit baseSize)
> 
> void GridTrack::setGrowthLimit(LayoutUnit growthLimit)
> {
>-    m_growthLimit = growthLimit == infinity ? growthLimit : std::min(growthLimit, m_growthLimitCap.value_or(growthLimit));
>+    m_growthLimit = growthLimit == infinity ? growthLimit : std::min(growthLimit, m_growthLimitCap.valueOr(growthLimit));
>     ensureGrowthLimitIsBiggerThanBaseSize();
> }
> 
>@@ -216,7 +216,7 @@ LayoutUnit GridTrackSizingAlgorithm::initialBaseSize(const GridTrackSize& trackS
> 
>     const Length& trackLength = gridLength.length();
>     if (trackLength.isSpecified())
>-        return valueForLength(trackLength, std::max<LayoutUnit>(availableSpace().value_or(0), 0));
>+        return valueForLength(trackLength, std::max<LayoutUnit>(availableSpace().valueOr(0), 0));
> 
>     ASSERT(trackLength.isMinContent() || trackLength.isAuto() || trackLength.isMaxContent());
>     return 0;
>@@ -230,7 +230,7 @@ LayoutUnit GridTrackSizingAlgorithm::initialGrowthLimit(const GridTrackSize& tra
> 
>     const Length& trackLength = gridLength.length();
>     if (trackLength.isSpecified())
>-        return valueForLength(trackLength, std::max<LayoutUnit>(availableSpace().value_or(0), 0));
>+        return valueForLength(trackLength, std::max<LayoutUnit>(availableSpace().valueOr(0), 0));
> 
>     ASSERT(trackLength.isMinContent() || trackLength.isAuto() || trackLength.isMaxContent());
>     return infinity;
>@@ -254,7 +254,7 @@ void GridTrackSizingAlgorithm::sizeTrackToFitNonSpanningItem(const GridSpan& spa
>     } else if (trackSize.hasMaxContentOrAutoMaxTrackBreadth()) {
>         LayoutUnit growthLimit = m_strategy->maxContentForChild(gridItem);
>         if (trackSize.isFitContent())
>-            growthLimit = std::min(growthLimit, valueForLength(trackSize.fitContentTrackBreadth().length(), availableSpace().value_or(0)));
>+            growthLimit = std::min(growthLimit, valueForLength(trackSize.fitContentTrackBreadth().length(), availableSpace().valueOr(0)));
>         track.setGrowthLimit(std::max(track.growthLimit(), growthLimit));
>     }
> }
>@@ -483,8 +483,8 @@ static bool sortByGridTrackGrowthPotential(const GridTrack* track1, const GridTr
>     if (track1HasInfiniteGrowthPotentialWithoutCap || track2HasInfiniteGrowthPotentialWithoutCap)
>         return track2HasInfiniteGrowthPotentialWithoutCap;
> 
>-    LayoutUnit track1Limit = track1->growthLimitCap().value_or(track1->growthLimit());
>-    LayoutUnit track2Limit = track2->growthLimitCap().value_or(track2->growthLimit());
>+    LayoutUnit track1Limit = track1->growthLimitCap().valueOr(track1->growthLimit());
>+    LayoutUnit track2Limit = track2->growthLimitCap().valueOr(track2->growthLimit());
>     return (track1Limit - track1->baseSize()) < (track2Limit - track2->baseSize());
> }
> 
>@@ -569,7 +569,7 @@ LayoutUnit GridTrackSizingAlgorithm::estimatedGridAreaBreadthForChild(const Rend
>         if (maxTrackSize.isContentSized() || maxTrackSize.isFlex() || isRelativeGridLengthAsAuto(maxTrackSize, direction))
>             gridAreaIsIndefinite = true;
>         else
>-            gridAreaSize += valueForLength(maxTrackSize.length(), availableSize.value_or(0_lu));
>+            gridAreaSize += valueForLength(maxTrackSize.length(), availableSize.valueOr(0_lu));
>     }
> 
>     gridAreaSize += m_renderGrid->guttersSize(m_grid, direction, span.startLine(), span.integerSpan(), availableSize);
>@@ -810,7 +810,7 @@ LayoutUnit GridTrackSizingAlgorithmStrategy::minSizeForChild(RenderBox& child) c
>             GridTrackSize trackSize = m_algorithm.gridTrackSize(direction(), trackPosition);
>             if (!trackSize.hasFixedMaxTrackBreadth())
>                 return minSize;
>-            maxBreadth += valueForLength(trackSize.maxTrackBreadth().length(), availableSpace().value_or(0_lu));
>+            maxBreadth += valueForLength(trackSize.maxTrackBreadth().length(), availableSpace().valueOr(0_lu));
>         }
>         if (minSize > maxBreadth) {
>             auto marginAndBorderAndPadding = GridLayoutFunctions::marginLogicalSizeForChild(*renderGrid(), direction(), child);
>@@ -831,7 +831,7 @@ LayoutUnit GridTrackSizingAlgorithmStrategy::minSizeForChild(RenderBox& child) c
>     bool overrideSizeHasChanged = updateOverrideContainingBlockContentSizeForChild(child, childInlineDirection, gridAreaSize);
>     layoutGridItemForMinSizeComputation(child, overrideSizeHasChanged);
> 
>-    return child.computeLogicalHeightUsing(MinSize, childMinSize, WTF::nullopt).value_or(0) + child.marginLogicalHeight() + child.scrollbarLogicalHeight() + baselineShim;
>+    return child.computeLogicalHeightUsing(MinSize, childMinSize, WTF::nullopt).valueOr(0) + child.marginLogicalHeight() + child.scrollbarLogicalHeight() + baselineShim;
> }
> 
> bool GridTrackSizingAlgorithm::canParticipateInBaselineAlignment(const RenderBox& child, GridAxis baselineAxis) const
>@@ -1101,7 +1101,7 @@ void GridTrackSizingAlgorithm::initializeTrackSizes()
>     Vector<GridTrack>& allTracks = tracks(m_direction);
>     const bool hasDefiniteFreeSpace = !!availableSpace();
>     const bool indefiniteHeight = m_direction == ForRows && !m_renderGrid->hasDefiniteLogicalHeight();
>-    LayoutUnit maxSize = std::max(0_lu, availableSpace().value_or(0_lu));
>+    LayoutUnit maxSize = std::max(0_lu, availableSpace().valueOr(0_lu));
>     // 1. Initialize per Grid track variables.
>     for (unsigned i = 0; i < allTracks.size(); ++i) {
>         GridTrack& track = allTracks[i];
>diff --git a/Source/WebCore/rendering/PaintInfo.h b/Source/WebCore/rendering/PaintInfo.h
>index 2321d4fa64c1e5245da2f3543be11123435a99be..4e1cfeee609a349a0a3d3d19544b5158edd9a5f9 100644
>--- a/Source/WebCore/rendering/PaintInfo.h
>+++ b/Source/WebCore/rendering/PaintInfo.h
>@@ -115,7 +115,7 @@ struct PaintInfo {
>         if (rect.isInfinite())
>             return;
> 
>-        FloatRect tranformedRect(localToAncestorTransform.inverse().value_or(AffineTransform()).mapRect(rect));
>+        FloatRect tranformedRect(localToAncestorTransform.inverse().valueOr(AffineTransform()).mapRect(rect));
>         rect.setLocation(LayoutPoint(tranformedRect.location()));
>         rect.setSize(LayoutSize(tranformedRect.size()));
>     }
>diff --git a/Source/WebCore/rendering/RenderBox.cpp b/Source/WebCore/rendering/RenderBox.cpp
>index aa737e490a4884f5ae2fc6f06ee4fa606df573df..a671111659e521562fef74db45743ef9bbfddce9 100644
>--- a/Source/WebCore/rendering/RenderBox.cpp
>+++ b/Source/WebCore/rendering/RenderBox.cpp
>@@ -2754,7 +2754,7 @@ RenderBox::LogicalExtentComputedValues RenderBox::computeLogicalHeight(LayoutUni
>         LayoutUnit heightResult;
>         if (checkMinMaxHeight) {
>             LayoutUnit intrinsicHeight = computedValues.m_extent - borderAndPaddingLogicalHeight();
>-            heightResult = computeLogicalHeightUsing(MainOrPreferredSize, style().logicalHeight(), intrinsicHeight).value_or(computedValues.m_extent);
>+            heightResult = computeLogicalHeightUsing(MainOrPreferredSize, style().logicalHeight(), intrinsicHeight).valueOr(computedValues.m_extent);
>             heightResult = constrainLogicalHeightByMinMax(heightResult, intrinsicHeight);
>         } else {
>             // The only times we don't check min/max height are when a fixed length has
>diff --git a/Source/WebCore/rendering/RenderCounter.cpp b/Source/WebCore/rendering/RenderCounter.cpp
>index 150ac065abd893fcb71ec20f1cf26305f8a94ed4..e5cde49006529a3aa7c8388cacc72cdf6532c07f 100644
>--- a/Source/WebCore/rendering/RenderCounter.cpp
>+++ b/Source/WebCore/rendering/RenderCounter.cpp
>@@ -167,7 +167,7 @@ static Optional<CounterPlan> planCounter(RenderElement& renderer, const AtomicSt
>     }
> 
>     if (directives.resetValue)
>-        return CounterPlan { true, saturatedAddition(*directives.resetValue, directives.incrementValue.value_or(0)) };
>+        return CounterPlan { true, saturatedAddition(*directives.resetValue, directives.incrementValue.valueOr(0)) };
>     if (directives.incrementValue)
>         return CounterPlan { false, *directives.incrementValue };
>     return WTF::nullopt;
>diff --git a/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp b/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp
>index 3483cba2b4fff594392d14ba9002b70251f6972c..b315e09459dc218e57dcce65f322ac8799839efb 100644
>--- a/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp
>+++ b/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp
>@@ -435,7 +435,7 @@ void RenderDeprecatedFlexibleBox::layoutHorizontalBox(bool relayoutChildren)
> 
>             // Update our height and overflow height.
>             if (style().boxAlign() == BoxAlignment::Baseline) {
>-                LayoutUnit ascent = child->firstLineBaseline().value_or(child->height() + child->marginBottom());
>+                LayoutUnit ascent = child->firstLineBaseline().valueOr(child->height() + child->marginBottom());
>                 ascent += child->marginTop();
>                 LayoutUnit descent = (child->height() + child->verticalMarginExtent()) - ascent;
> 
>@@ -510,7 +510,7 @@ void RenderDeprecatedFlexibleBox::layoutHorizontalBox(bool relayoutChildren)
>                 childY += child->marginTop() + std::max<LayoutUnit>(0, (contentHeight() - (child->height() + child->verticalMarginExtent())) / 2);
>                 break;
>             case BoxAlignment::Baseline: {
>-                LayoutUnit ascent = child->firstLineBaseline().value_or(child->height() + child->marginBottom());
>+                LayoutUnit ascent = child->firstLineBaseline().valueOr(child->height() + child->marginBottom());
>                 ascent += child->marginTop();
>                 childY += child->marginTop() + (maxAscent - ascent);
>                 break;
>diff --git a/Source/WebCore/rendering/RenderFlexibleBox.cpp b/Source/WebCore/rendering/RenderFlexibleBox.cpp
>index 7949fbf3407f466fa66e5120f41a6f04d2ea978e..b30fc7f92f786e9943a9a9709e1deaa25309473a 100644
>--- a/Source/WebCore/rendering/RenderFlexibleBox.cpp
>+++ b/Source/WebCore/rendering/RenderFlexibleBox.cpp
>@@ -172,7 +172,7 @@ static int synthesizedBaselineFromContentBox(const RenderBox& box, LineDirection
> 
> int RenderFlexibleBox::baselinePosition(FontBaseline, bool, LineDirectionMode direction, LinePositionMode) const
> {
>-    int baseline = firstLineBaseline().value_or(synthesizedBaselineFromContentBox(*this, direction));
>+    int baseline = firstLineBaseline().valueOr(synthesizedBaselineFromContentBox(*this, direction));
> 
>     int marginAscent = direction == HorizontalLine ? marginTop() : marginRight();
>     return baseline + marginAscent;
>@@ -1036,7 +1036,7 @@ bool RenderFlexibleBox::updateAutoMarginsInCrossAxis(RenderBox& child, LayoutUni
> 
> LayoutUnit RenderFlexibleBox::marginBoxAscentForChild(const RenderBox& child)
> {
>-    LayoutUnit ascent = child.firstLineBaseline().value_or(crossAxisExtentForChild(child));
>+    LayoutUnit ascent = child.firstLineBaseline().valueOr(crossAxisExtentForChild(child));
>     return ascent + flowAwareMarginBeforeForChild(child);
> }
> 
>@@ -1074,12 +1074,12 @@ LayoutUnit RenderFlexibleBox::adjustChildSizeForMinAndMax(const RenderBox& child
>     Optional<LayoutUnit> maxExtent = WTF::nullopt;
>     if (max.isSpecifiedOrIntrinsic()) {
>         maxExtent = computeMainAxisExtentForChild(child, MaxSize, max);
>-        childSize = std::min(childSize, maxExtent.value_or(childSize));
>+        childSize = std::min(childSize, maxExtent.valueOr(childSize));
>     }
> 
>     Length min = isHorizontalFlow() ? child.style().minWidth() : child.style().minHeight();
>     if (min.isSpecifiedOrIntrinsic())
>-        return std::max(childSize, std::max(0_lu, computeMainAxisExtentForChild(child, MinSize, min).value_or(childSize)));
>+        return std::max(childSize, std::max(0_lu, computeMainAxisExtentForChild(child, MinSize, min).valueOr(childSize)));
>     
>     if (!isFlexibleBoxImpl() && min.isAuto() && mainAxisOverflowForChild(child) == Overflow::Visible && !(isColumnFlow() && is<RenderFlexibleBox>(child))) {
>         // FIXME: For now, we do not handle min-height: auto for nested
>@@ -1089,17 +1089,17 @@ LayoutUnit RenderFlexibleBox::adjustChildSizeForMinAndMax(const RenderBox& child
>         // css-flexbox section 4.5
>         // FIXME: If the min value is expected to be valid here, we need to come up with a non optional version of computeMainAxisExtentForChild and
>         // ensure it's valid through the virtual calls of computeIntrinsicLogicalContentHeightUsing.
>-        LayoutUnit contentSize = computeMainAxisExtentForChild(child, MinSize, Length(MinContent)).value_or(0);
>+        LayoutUnit contentSize = computeMainAxisExtentForChild(child, MinSize, Length(MinContent)).valueOr(0);
>         ASSERT(contentSize >= 0);
>         if (child.hasAspectRatio() && child.intrinsicSize().height() > 0)
>             contentSize = adjustChildSizeForAspectRatioCrossAxisMinAndMax(child, contentSize);
>-        contentSize = std::min(contentSize, maxExtent.value_or(contentSize));
>+        contentSize = std::min(contentSize, maxExtent.valueOr(contentSize));
>         
>         Length mainSize = isHorizontalFlow() ? child.style().width() : child.style().height();
>         if (mainAxisLengthIsDefinite(child, mainSize)) {
>-            LayoutUnit resolvedMainSize = computeMainAxisExtentForChild(child, MainOrPreferredSize, mainSize).value_or(0);
>+            LayoutUnit resolvedMainSize = computeMainAxisExtentForChild(child, MainOrPreferredSize, mainSize).valueOr(0);
>             ASSERT(resolvedMainSize >= 0);
>-            LayoutUnit specifiedSize = std::min(resolvedMainSize, maxExtent.value_or(resolvedMainSize));
>+            LayoutUnit specifiedSize = std::min(resolvedMainSize, maxExtent.valueOr(resolvedMainSize));
>             return std::max(childSize, std::min(specifiedSize, contentSize));
>         }
> 
>diff --git a/Source/WebCore/rendering/RenderGrid.cpp b/Source/WebCore/rendering/RenderGrid.cpp
>index 04bb2b6cba21a9e91f4a7936e78915a0ec97eef4..35a610b29973ccd9e68c654c8a45bed0cc3a5a6f 100644
>--- a/Source/WebCore/rendering/RenderGrid.cpp
>+++ b/Source/WebCore/rendering/RenderGrid.cpp
>@@ -310,7 +310,7 @@ LayoutUnit RenderGrid::gridGap(GridTrackSizingDirection direction, Optional<Layo
>     if (gapLength.isNormal())
>         return 0_lu;
> 
>-    return valueForLength(gapLength.length(), availableSize.value_or(0));
>+    return valueForLength(gapLength.length(), availableSize.valueOr(0));
> }
> 
> LayoutUnit RenderGrid::gridGap(GridTrackSizingDirection direction) const
>@@ -1226,7 +1226,7 @@ int RenderGrid::baselinePosition(FontBaseline, bool, LineDirectionMode direction
> #else
>     UNUSED_PARAM(mode);
> #endif
>-    return firstLineBaseline().value_or(synthesizedBaselineFromMarginBox(*this, direction));
>+    return firstLineBaseline().valueOr(synthesizedBaselineFromMarginBox(*this, direction));
> }
> 
> Optional<int> RenderGrid::firstLineBaseline() const
>diff --git a/Source/WebCore/rendering/RenderLayer.cpp b/Source/WebCore/rendering/RenderLayer.cpp
>index c26e6b79fd61f66ef2589d096c6a230dcf3c8d49..0e2e0f16b4490034f3b9af7b4c3dbfd51034bc01 100644
>--- a/Source/WebCore/rendering/RenderLayer.cpp
>+++ b/Source/WebCore/rendering/RenderLayer.cpp
>@@ -4457,7 +4457,7 @@ void RenderLayer::paintLayerByApplyingTransform(GraphicsContext& context, const
>     LayoutSize adjustedSubpixelOffset = offsetForThisLayer - LayoutSize(devicePixelSnappedOffsetForThisLayer);
>     LayerPaintingInfo transformedPaintingInfo(paintingInfo);
>     transformedPaintingInfo.rootLayer = this;
>-    transformedPaintingInfo.paintDirtyRect = LayoutRect(encloseRectToDevicePixels(transform.inverse().value_or(AffineTransform()).mapRect(paintingInfo.paintDirtyRect), deviceScaleFactor));
>+    transformedPaintingInfo.paintDirtyRect = LayoutRect(encloseRectToDevicePixels(transform.inverse().valueOr(AffineTransform()).mapRect(paintingInfo.paintDirtyRect), deviceScaleFactor));
>     transformedPaintingInfo.subpixelOffset = adjustedSubpixelOffset;
>     paintLayerContentsAndReflection(context, transformedPaintingInfo, paintFlags);
>     context.setCTM(oldTransfrom);
>diff --git a/Source/WebCore/rendering/RenderListBox.cpp b/Source/WebCore/rendering/RenderListBox.cpp
>index 670e374655c13c5e8badd28fe18237cd3846f264..63ade7e23e4367fceabe01f46683db32fe81ad61 100644
>--- a/Source/WebCore/rendering/RenderListBox.cpp
>+++ b/Source/WebCore/rendering/RenderListBox.cpp
>@@ -302,7 +302,7 @@ LayoutRect RenderListBox::itemBoundingBoxRect(const LayoutPoint& additionalOffse
> void RenderListBox::paintItem(PaintInfo& paintInfo, const LayoutPoint& paintOffset, const PaintFunction& paintFunction)
> {
>     int listItemsSize = numItems();
>-    int firstVisibleItem = m_indexOfFirstVisibleItemInsidePaddingTopArea.value_or(m_indexOffset);
>+    int firstVisibleItem = m_indexOfFirstVisibleItemInsidePaddingTopArea.valueOr(m_indexOffset);
>     int endIndex = firstVisibleItem + numVisibleItems(ConsiderPadding::Yes);
>     for (int i = firstVisibleItem; i < listItemsSize && i < endIndex; ++i)
>         paintFunction(paintInfo, paintOffset, i);
>@@ -621,7 +621,7 @@ bool RenderListBox::scrollToRevealElementAtListIndex(int index)
> 
> bool RenderListBox::listIndexIsVisible(int index)
> {
>-    int firstIndex = m_indexOfFirstVisibleItemInsidePaddingTopArea.value_or(m_indexOffset);
>+    int firstIndex = m_indexOfFirstVisibleItemInsidePaddingTopArea.valueOr(m_indexOffset);
>     int endIndex = m_indexOfFirstVisibleItemInsidePaddingBottomArea
>         ? m_indexOfFirstVisibleItemInsidePaddingBottomArea.value() + numberOfVisibleItemsInPaddingBottom()
>         : m_indexOffset + numVisibleItems();
>diff --git a/Source/WebCore/rendering/RenderMultiColumnSet.cpp b/Source/WebCore/rendering/RenderMultiColumnSet.cpp
>index dbb8ac58a1fde8b4ae269d65b0d151b882bdc227..28dfeb31264c20a846d72c935f30f41f99205cc2 100644
>--- a/Source/WebCore/rendering/RenderMultiColumnSet.cpp
>+++ b/Source/WebCore/rendering/RenderMultiColumnSet.cpp
>@@ -420,7 +420,7 @@ LayoutUnit RenderMultiColumnSet::calculateMaxColumnHeight() const
>     LayoutUnit availableHeight = multiColumnFlow()->columnHeightAvailable();
>     LayoutUnit maxColumnHeight = availableHeight ? availableHeight : RenderFragmentedFlow::maxLogicalHeight();
>     if (!multicolStyle.logicalMaxHeight().isUndefined())
>-        maxColumnHeight = std::min(maxColumnHeight, multicolBlock->computeContentLogicalHeight(MaxSize, multicolStyle.logicalMaxHeight(), WTF::nullopt).value_or(maxColumnHeight));
>+        maxColumnHeight = std::min(maxColumnHeight, multicolBlock->computeContentLogicalHeight(MaxSize, multicolStyle.logicalMaxHeight(), WTF::nullopt).valueOr(maxColumnHeight));
>     return heightAdjustedForSetOffset(maxColumnHeight);
> }
> 
>diff --git a/Source/WebCore/rendering/RenderTable.cpp b/Source/WebCore/rendering/RenderTable.cpp
>index 0b03604293901b32cd0577ce3557ce75d4a7e295..99ad8da48f24d2fc2564774d252547fdbe001069 100644
>--- a/Source/WebCore/rendering/RenderTable.cpp
>+++ b/Source/WebCore/rendering/RenderTable.cpp
>@@ -322,9 +322,9 @@ LayoutUnit RenderTable::convertStyleLogicalHeightToComputedHeight(const Length&
>         }
>         return styleLogicalHeight.value() - borders;
>     } else if (styleLogicalHeight.isPercentOrCalculated())
>-        return computePercentageLogicalHeight(styleLogicalHeight).value_or(0);
>+        return computePercentageLogicalHeight(styleLogicalHeight).valueOr(0);
>     else if (styleLogicalHeight.isIntrinsic())
>-        return computeIntrinsicLogicalContentHeightUsing(styleLogicalHeight, logicalHeight() - borderAndPadding, borderAndPadding).value_or(0);
>+        return computeIntrinsicLogicalContentHeightUsing(styleLogicalHeight, logicalHeight() - borderAndPadding, borderAndPadding).valueOr(0);
>     else
>         ASSERT_NOT_REACHED();
>     return 0_lu;
>diff --git a/Source/WebCore/rendering/RenderTableCell.cpp b/Source/WebCore/rendering/RenderTableCell.cpp
>index 8dd66a46c10b45e0dda9dabfdef66bdae7c5b785..f5a0fd0d3126cabcbcc7a7d73de004a8f37f4583 100644
>--- a/Source/WebCore/rendering/RenderTableCell.cpp
>+++ b/Source/WebCore/rendering/RenderTableCell.cpp
>@@ -410,7 +410,7 @@ LayoutUnit RenderTableCell::cellBaselinePosition() const
>     // <http://www.w3.org/TR/2007/CR-CSS21-20070719/tables.html#height-layout>: The baseline of a cell is the baseline of
>     // the first in-flow line box in the cell, or the first in-flow table-row in the cell, whichever comes first. If there
>     // is no such line box or table-row, the baseline is the bottom of content edge of the cell box.
>-    return firstLineBaseline().value_or(borderAndPaddingBefore() + contentLogicalHeight());
>+    return firstLineBaseline().valueOr(borderAndPaddingBefore() + contentLogicalHeight());
> }
> 
> static inline void markCellDirtyWhenCollapsedBorderChanges(RenderTableCell* cell)
>diff --git a/Source/WebCore/rendering/RenderTableSection.cpp b/Source/WebCore/rendering/RenderTableSection.cpp
>index 9119312549c1dc3f09406f96af021e0bccc3f109..d1db9f285f9962814f8b77b2210fe3e8e3a5c61e 100644
>--- a/Source/WebCore/rendering/RenderTableSection.cpp
>+++ b/Source/WebCore/rendering/RenderTableSection.cpp
>@@ -888,7 +888,7 @@ Optional<int> RenderTableSection::firstLineBaseline() const
>         // Only cells with content have a baseline
>         if (cell && cell->contentLogicalHeight()) {
>             int candidate = roundToInt(cell->logicalTop() + cell->borderAndPaddingBefore() + cell->contentLogicalHeight());
>-            result = std::max(result.value_or(candidate), candidate);
>+            result = std::max(result.valueOr(candidate), candidate);
>         }
>     }
> 
>diff --git a/Source/WebCore/rendering/RenderText.cpp b/Source/WebCore/rendering/RenderText.cpp
>index 431b8fe73b7b8f4692b14eb0eb4e39e55791a768..8c1788a2376d972c9f5960c74fb8cdb186ab2cfa 100644
>--- a/Source/WebCore/rendering/RenderText.cpp
>+++ b/Source/WebCore/rendering/RenderText.cpp
>@@ -1004,7 +1004,7 @@ void RenderText::computePreferredLogicalWidths(float leadWidth, HashSet<const Fo
>         }
>     }
> 
>-    glyphOverflow.left = firstGlyphLeftOverflow.value_or(glyphOverflow.left);
>+    glyphOverflow.left = firstGlyphLeftOverflow.valueOr(glyphOverflow.left);
> 
>     if ((needsWordSpacing && length > 1) || (ignoringSpaces && !firstWord))
>         currMaxWidth += wordSpacing;
>@@ -1510,13 +1510,13 @@ int RenderText::previousOffset(int current) const
>         return current - 1;
> 
>     CachedTextBreakIterator iterator(text(), TextBreakIterator::Mode::Caret, nullAtom());
>-    return iterator.preceding(current).value_or(current - 1);
>+    return iterator.preceding(current).valueOr(current - 1);
> }
> 
> int RenderText::previousOffsetForBackwardDeletion(int current) const
> {
>     CachedTextBreakIterator iterator(text(), TextBreakIterator::Mode::Delete, nullAtom());
>-    return iterator.preceding(current).value_or(0);
>+    return iterator.preceding(current).valueOr(0);
> }
> 
> int RenderText::nextOffset(int current) const
>@@ -1525,7 +1525,7 @@ int RenderText::nextOffset(int current) const
>         return current + 1;
> 
>     CachedTextBreakIterator iterator(text(), TextBreakIterator::Mode::Caret, nullAtom());
>-    return iterator.following(current).value_or(current + 1);
>+    return iterator.following(current).valueOr(current + 1);
> }
> 
> bool RenderText::computeCanUseSimpleFontCodePath() const
>@@ -1547,7 +1547,7 @@ void RenderText::momentarilyRevealLastTypedCharacter(unsigned offsetAfterLastTyp
> 
> StringView RenderText::stringView(unsigned start, Optional<unsigned> stop) const
> {
>-    unsigned destination = stop.value_or(text().length());
>+    unsigned destination = stop.valueOr(text().length());
>     ASSERT(start <= length());
>     ASSERT(destination <= length());
>     ASSERT(start <= destination);
>diff --git a/Source/WebCore/rendering/RenderView.cpp b/Source/WebCore/rendering/RenderView.cpp
>index 967692ee0a2c33457d777732424ec791a4fccead..e8dd849f169122d2553d8bc9f544dbd16b4148e0 100644
>--- a/Source/WebCore/rendering/RenderView.cpp
>+++ b/Source/WebCore/rendering/RenderView.cpp
>@@ -234,7 +234,7 @@ void RenderView::layout()
>     if (!needsLayout())
>         return;
> 
>-    LayoutStateMaintainer statePusher(*this, { }, false, m_pageLogicalSize.value_or(LayoutSize()).height(), m_pageLogicalHeightChanged);
>+    LayoutStateMaintainer statePusher(*this, { }, false, m_pageLogicalSize.valueOr(LayoutSize()).height(), m_pageLogicalHeightChanged);
> 
>     m_pageLogicalHeightChanged = false;
> 
>diff --git a/Source/WebCore/rendering/mathml/RenderMathMLBlock.cpp b/Source/WebCore/rendering/mathml/RenderMathMLBlock.cpp
>index c9e3513133a7a3e0bb6349ca5b34a35afd29192f..8e356b6b696670cf5556d193b61751e42dd5c1d6 100644
>--- a/Source/WebCore/rendering/mathml/RenderMathMLBlock.cpp
>+++ b/Source/WebCore/rendering/mathml/RenderMathMLBlock.cpp
>@@ -102,7 +102,7 @@ int RenderMathMLBlock::baselinePosition(FontBaseline baselineType, bool firstLin
>     if (linePositionMode == PositionOfInteriorLineBoxes)
>         return 0;
> 
>-    return firstLineBaseline().value_or(RenderBlock::baselinePosition(baselineType, firstLine, direction, linePositionMode));
>+    return firstLineBaseline().valueOr(RenderBlock::baselinePosition(baselineType, firstLine, direction, linePositionMode));
> }
> 
> #if ENABLE(DEBUG_MATH_LAYOUT)
>diff --git a/Source/WebCore/rendering/mathml/RenderMathMLBlock.h b/Source/WebCore/rendering/mathml/RenderMathMLBlock.h
>index 048c7ec885288c194dae2d2db1110a971cc482ca..2d4393b52dffcb821bfd7c94851cd779a19eb740 100644
>--- a/Source/WebCore/rendering/mathml/RenderMathMLBlock.h
>+++ b/Source/WebCore/rendering/mathml/RenderMathMLBlock.h
>@@ -80,7 +80,7 @@ protected:
> 
>     static LayoutUnit ascentForChild(const RenderBox& child)
>     {
>-        return child.firstLineBaseline().value_or(child.logicalHeight());
>+        return child.firstLineBaseline().valueOr(child.logicalHeight());
>     }
> 
>     void layoutBlock(bool relayoutChildren, LayoutUnit pageLogicalHeight = 0_lu) override;
>diff --git a/Source/WebCore/rendering/style/GridPosition.cpp b/Source/WebCore/rendering/style/GridPosition.cpp
>index f12d3afe6fcfc825705c9c4c96847e17b4b10d21..d4e731a090a22da6f61cc312fe160882580f7850 100644
>--- a/Source/WebCore/rendering/style/GridPosition.cpp
>+++ b/Source/WebCore/rendering/style/GridPosition.cpp
>@@ -85,7 +85,7 @@ int GridPosition::spanPosition() const
> 
> int GridPosition::max()
> {
>-    return gMaxPositionForTesting.value_or(kGridMaxPosition);
>+    return gMaxPositionForTesting.valueOr(kGridMaxPosition);
> }
> 
> int GridPosition::min()
>diff --git a/Source/WebCore/rendering/style/TextUnderlineOffset.h b/Source/WebCore/rendering/style/TextUnderlineOffset.h
>index 807e4db8b798843f337536f95e888c780af92499..38ed93c91f6cb9f64c2cf20b3cbaf042b4a81b6b 100644
>--- a/Source/WebCore/rendering/style/TextUnderlineOffset.h
>+++ b/Source/WebCore/rendering/style/TextUnderlineOffset.h
>@@ -68,7 +68,7 @@ public:
> 
>     float lengthOr(float defaultValue) const
>     {
>-        return m_length.value_or(defaultValue);
>+        return m_length.valueOr(defaultValue);
>     }
> 
>     bool operator==(const TextUnderlineOffset& other) const
>diff --git a/Source/WebCore/rendering/svg/RenderSVGContainer.cpp b/Source/WebCore/rendering/svg/RenderSVGContainer.cpp
>index cbe270b11c8331a47fe88f8ba5e01a7ab8262bb9..98b315d67443e56ba404c2512ec125a45a608bdc 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGContainer.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGContainer.cpp
>@@ -161,7 +161,7 @@ bool RenderSVGContainer::nodeAtFloatPoint(const HitTestRequest& request, HitTest
>     if (!pointIsInsideViewportClip(pointInParent))
>         return false;
> 
>-    FloatPoint localPoint = localToParentTransform().inverse().value_or(AffineTransform()).mapPoint(pointInParent);
>+    FloatPoint localPoint = localToParentTransform().inverse().valueOr(AffineTransform()).mapPoint(pointInParent);
> 
>     if (!SVGRenderSupport::pointInClippingArea(*this, localPoint))
>         return false;
>diff --git a/Source/WebCore/rendering/svg/RenderSVGForeignObject.cpp b/Source/WebCore/rendering/svg/RenderSVGForeignObject.cpp
>index dfb4b8766e8d37082350aa7a5c0151dea457855f..585c7be797eaa4cb22ee214c010a766f68f6b407 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGForeignObject.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGForeignObject.cpp
>@@ -185,7 +185,7 @@ bool RenderSVGForeignObject::nodeAtFloatPoint(const HitTestRequest& request, Hit
>     if (hitTestAction != HitTestForeground)
>         return false;
> 
>-    FloatPoint localPoint = localTransform().inverse().value_or(AffineTransform()).mapPoint(pointInParent);
>+    FloatPoint localPoint = localTransform().inverse().valueOr(AffineTransform()).mapPoint(pointInParent);
> 
>     // Early exit if local point is not contained in clipped viewport area
>     if (SVGRenderSupport::isOverflowHidden(*this) && !m_viewport.contains(localPoint))
>diff --git a/Source/WebCore/rendering/svg/RenderSVGImage.cpp b/Source/WebCore/rendering/svg/RenderSVGImage.cpp
>index 0a58f8fd1ad249483dd50dbbdb391fd7af94f3e4..2c6f3178eeb26c7b2c0d95ae108b7efcc6e22c4e 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGImage.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGImage.cpp
>@@ -193,7 +193,7 @@ bool RenderSVGImage::nodeAtFloatPoint(const HitTestRequest& request, HitTestResu
>     PointerEventsHitRules hitRules(PointerEventsHitRules::SVG_IMAGE_HITTESTING, request, style().pointerEvents());
>     bool isVisible = (style().visibility() == Visibility::Visible);
>     if (isVisible || !hitRules.requireVisible) {
>-        FloatPoint localPoint = localToParentTransform().inverse().value_or(AffineTransform()).mapPoint(pointInParent);
>+        FloatPoint localPoint = localToParentTransform().inverse().valueOr(AffineTransform()).mapPoint(pointInParent);
>             
>         if (!SVGRenderSupport::pointInClippingArea(*this, localPoint))
>             return false;
>diff --git a/Source/WebCore/rendering/svg/RenderSVGResourceClipper.cpp b/Source/WebCore/rendering/svg/RenderSVGResourceClipper.cpp
>index 7398ef32b3860c2365554344ddfa30412a48a80a..2cf86e25f626ee2bde25859659fc1e06676e00f5 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGResourceClipper.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGResourceClipper.cpp
>@@ -268,10 +268,10 @@ bool RenderSVGResourceClipper::hitTestClipContent(const FloatRect& objectBoundin
>         AffineTransform transform;
>         transform.translate(objectBoundingBox.location());
>         transform.scale(objectBoundingBox.size());
>-        point = transform.inverse().value_or(AffineTransform()).mapPoint(point);
>+        point = transform.inverse().valueOr(AffineTransform()).mapPoint(point);
>     }
> 
>-    point = clipPathElement().animatedLocalTransform().inverse().value_or(AffineTransform()).mapPoint(point);
>+    point = clipPathElement().animatedLocalTransform().inverse().valueOr(AffineTransform()).mapPoint(point);
> 
>     for (Node* childNode = clipPathElement().firstChild(); childNode; childNode = childNode->nextSibling()) {
>         RenderObject* renderer = childNode->renderer();
>diff --git a/Source/WebCore/rendering/svg/RenderSVGResourceFilter.cpp b/Source/WebCore/rendering/svg/RenderSVGResourceFilter.cpp
>index 36406921be80d78139bd69a5205236258d72a054..1b3ef24cc92d2052a34aad20882330e1a123b84f 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGResourceFilter.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGResourceFilter.cpp
>@@ -276,7 +276,7 @@ void RenderSVGResourceFilter::postApplyResource(RenderElement& renderer, Graphic
> 
>         ImageBuffer* resultImage = lastEffect->imageBufferResult();
>         if (resultImage) {
>-            context->concatCTM(filterData.shearFreeAbsoluteTransform.inverse().value_or(AffineTransform()));
>+            context->concatCTM(filterData.shearFreeAbsoluteTransform.inverse().valueOr(AffineTransform()));
> 
>             context->scale(FloatSize(1 / filterData.filter->filterResolution().width(), 1 / filterData.filter->filterResolution().height()));
>             context->drawImageBuffer(*resultImage, lastEffect->absolutePaintRect());
>diff --git a/Source/WebCore/rendering/svg/RenderSVGRoot.cpp b/Source/WebCore/rendering/svg/RenderSVGRoot.cpp
>index e1502ef75bebf677f617c42184450b680f7100a8..df0ef6f6f3ed8e3d4212994a9e0337642510cb59 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGRoot.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGRoot.cpp
>@@ -405,7 +405,7 @@ bool RenderSVGRoot::nodeAtPoint(const HitTestRequest& request, HitTestResult& re
>     // Test SVG content if the point is in our content box or it is inside the visualOverflowRect and the overflow is visible.
>     // FIXME: This should be an intersection when rect-based hit tests are supported by nodeAtFloatPoint.
>     if (contentBoxRect().contains(pointInBorderBox) || (!shouldApplyViewportClip() && visualOverflowRect().contains(pointInParent))) {
>-        FloatPoint localPoint = localToParentTransform().inverse().value_or(AffineTransform()).mapPoint(FloatPoint(pointInParent));
>+        FloatPoint localPoint = localToParentTransform().inverse().valueOr(AffineTransform()).mapPoint(FloatPoint(pointInParent));
> 
>         for (RenderObject* child = lastChild(); child; child = child->previousSibling()) {
>             // FIXME: nodeAtFloatPoint() doesn't handle rect-based hit tests yet.
>diff --git a/Source/WebCore/rendering/svg/RenderSVGShape.cpp b/Source/WebCore/rendering/svg/RenderSVGShape.cpp
>index fa3bc9170c3503b40a6b12cb0515ccd395504013..34b0ae75bdc0056576d51380185efe6bc72c706e 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGShape.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGShape.cpp
>@@ -368,7 +368,7 @@ bool RenderSVGShape::nodeAtFloatPoint(const HitTestRequest& request, HitTestResu
>     if (hitTestAction != HitTestForeground)
>         return false;
> 
>-    FloatPoint localPoint = m_localTransform.inverse().value_or(AffineTransform()).mapPoint(pointInParent);
>+    FloatPoint localPoint = m_localTransform.inverse().valueOr(AffineTransform()).mapPoint(pointInParent);
> 
>     if (!SVGRenderSupport::pointInClippingArea(*this, localPoint))
>         return false;
>diff --git a/Source/WebCore/rendering/svg/RenderSVGText.cpp b/Source/WebCore/rendering/svg/RenderSVGText.cpp
>index 637d8c4fd844a44fed9492ffc9e5188d0723b28d..c80e956d55d8da48368a5db46918b3b56a533e5f 100644
>--- a/Source/WebCore/rendering/svg/RenderSVGText.cpp
>+++ b/Source/WebCore/rendering/svg/RenderSVGText.cpp
>@@ -439,7 +439,7 @@ bool RenderSVGText::nodeAtFloatPoint(const HitTestRequest& request, HitTestResul
>     if (isVisible || !hitRules.requireVisible) {
>         if ((hitRules.canHitStroke && (style().svgStyle().hasStroke() || !hitRules.requireStroke))
>             || (hitRules.canHitFill && (style().svgStyle().hasFill() || !hitRules.requireFill))) {
>-            FloatPoint localPoint = localToParentTransform().inverse().value_or(AffineTransform()).mapPoint(pointInParent);
>+            FloatPoint localPoint = localToParentTransform().inverse().valueOr(AffineTransform()).mapPoint(pointInParent);
> 
>             if (!SVGRenderSupport::pointInClippingArea(*this, localPoint))
>                 return false;       
>diff --git a/Source/WebCore/rendering/svg/SVGRenderingContext.cpp b/Source/WebCore/rendering/svg/SVGRenderingContext.cpp
>index 495b134bb36f0da0474cc709b7cd196f5996c7a1..aa92d634ecef80e9068a81157837028e6c61f3ed 100644
>--- a/Source/WebCore/rendering/svg/SVGRenderingContext.cpp
>+++ b/Source/WebCore/rendering/svg/SVGRenderingContext.cpp
>@@ -316,7 +316,7 @@ void SVGRenderingContext::clipToImageBuffer(GraphicsContext& context, const Affi
> 
>     // The mask image has been created in the absolute coordinate space, as the image should not be scaled.
>     // So the actual masking process has to be done in the absolute coordinate space as well.
>-    context.concatCTM(absoluteTransform.inverse().value_or(AffineTransform()));
>+    context.concatCTM(absoluteTransform.inverse().valueOr(AffineTransform()));
>     context.clipToImageBuffer(*imageBuffer, absoluteTargetRect);
>     context.concatCTM(absoluteTransform);
> 
>diff --git a/Source/WebCore/svg/SVGToOTFFontConversion.cpp b/Source/WebCore/svg/SVGToOTFFontConversion.cpp
>index 902e54cb9e27adbe4502bee6276b3cdfec016b65..dfe875578aae0b62c58b75db96edd777bea1f648 100644
>--- a/Source/WebCore/svg/SVGToOTFFontConversion.cpp
>+++ b/Source/WebCore/svg/SVGToOTFFontConversion.cpp
>@@ -1297,7 +1297,7 @@ void SVGToOTFFontConverter::processGlyphElement(const SVGElement& glyphOrMissing
>     if (glyphBoundingBox)
>         m_minRightSideBearing = std::min(m_minRightSideBearing, horizontalAdvance - glyphBoundingBox.value().maxX());
> 
>-    m_glyphs.append(GlyphData(WTFMove(path), glyphElement, horizontalAdvance, verticalAdvance, glyphBoundingBox.value_or(FloatRect()), codepoints));
>+    m_glyphs.append(GlyphData(WTFMove(path), glyphElement, horizontalAdvance, verticalAdvance, glyphBoundingBox.valueOr(FloatRect()), codepoints));
> }
> 
> void SVGToOTFFontConverter::appendLigatureGlyphs()
>@@ -1421,7 +1421,7 @@ SVGToOTFFontConverter::SVGToOTFFontConverter(const SVGFontElement& fontElement)
>             processGlyphElement(glyphElement, &glyphElement, defaultHorizontalAdvance, defaultVerticalAdvance, unicodeAttribute, boundingBox);
>     }
> 
>-    m_boundingBox = boundingBox.value_or(FloatRect());
>+    m_boundingBox = boundingBox.valueOr(FloatRect());
> 
>     appendLigatureGlyphs();
> 
>diff --git a/Source/WebDriver/Session.cpp b/Source/WebDriver/Session.cpp
>index 0c63a20aa1241cf9a9f74e3c6100aa4578bfda34..df28199a6f43b812cd99503e8ea833f5ddb8171e 100644
>--- a/Source/WebDriver/Session.cpp
>+++ b/Source/WebDriver/Session.cpp
>@@ -219,7 +219,7 @@ void Session::handleUserPrompts(Function<void (CommandResult&&)>&& completionHan
> 
> void Session::handleUnexpectedAlertOpen(Function<void (CommandResult&&)>&& completionHandler)
> {
>-    switch (capabilities().unhandledPromptBehavior.value_or(UnhandledPromptBehavior::DismissAndNotify)) {
>+    switch (capabilities().unhandledPromptBehavior.valueOr(UnhandledPromptBehavior::DismissAndNotify)) {
>     case UnhandledPromptBehavior::Dismiss:
>         dismissAlert(WTFMove(completionHandler));
>         break;
>@@ -911,7 +911,7 @@ void Session::computeElementLayout(const String& elementID, OptionSet<ElementLay
> 
>     RefPtr<JSON::Object> parameters = JSON::Object::create();
>     parameters->setString("browsingContextHandle"_s, m_toplevelBrowsingContext.value());
>-    parameters->setString("frameHandle"_s, m_currentBrowsingContext.value_or(emptyString()));
>+    parameters->setString("frameHandle"_s, m_currentBrowsingContext.valueOr(emptyString()));
>     parameters->setString("nodeHandle"_s, elementID);
>     parameters->setBoolean("scrollIntoViewIfNeeded"_s, options.contains(ElementLayoutOption::ScrollIntoViewIfNeeded));
>     parameters->setString("coordinateSystem"_s, options.contains(ElementLayoutOption::UseViewportCoordinates) ? "LayoutViewport"_s : "Page"_s);
>@@ -1496,7 +1496,7 @@ void Session::selectOptionElement(const String& elementID, Function<void (Comman
> {
>     RefPtr<JSON::Object> parameters = JSON::Object::create();
>     parameters->setString("browsingContextHandle"_s, m_toplevelBrowsingContext.value());
>-    parameters->setString("frameHandle"_s, m_currentBrowsingContext.value_or(emptyString()));
>+    parameters->setString("frameHandle"_s, m_currentBrowsingContext.valueOr(emptyString()));
>     parameters->setString("nodeHandle"_s, elementID);
>     m_host->sendCommandToBackend("selectOptionElement"_s, WTFMove(parameters), [protectedThis = makeRef(*this), completionHandler = WTFMove(completionHandler)](SessionHost::CommandResponse&& response) {
>         if (response.isError) {
>@@ -2004,12 +2004,12 @@ static RefPtr<JSON::Object> builtAutomationCookie(const Session::Cookie& cookie)
>     RefPtr<JSON::Object> cookieObject = JSON::Object::create();
>     cookieObject->setString("name"_s, cookie.name);
>     cookieObject->setString("value"_s, cookie.value);
>-    cookieObject->setString("path"_s, cookie.path.value_or("/"));
>-    cookieObject->setString("domain"_s, cookie.domain.value_or(emptyString()));
>-    cookieObject->setBoolean("secure"_s, cookie.secure.value_or(false));
>-    cookieObject->setBoolean("httpOnly"_s, cookie.httpOnly.value_or(false));
>+    cookieObject->setString("path"_s, cookie.path.valueOr("/"));
>+    cookieObject->setString("domain"_s, cookie.domain.valueOr(emptyString()));
>+    cookieObject->setBoolean("secure"_s, cookie.secure.valueOr(false));
>+    cookieObject->setBoolean("httpOnly"_s, cookie.httpOnly.valueOr(false));
>     cookieObject->setBoolean("session"_s, !cookie.expiry);
>-    cookieObject->setDouble("expires"_s, cookie.expiry.value_or(0));
>+    cookieObject->setDouble("expires"_s, cookie.expiry.valueOr(0));
>     return cookieObject;
> }
> 
>@@ -2466,7 +2466,7 @@ void Session::takeScreenshot(Optional<String> elementID, Optional<bool> scrollIn
>             parameters->setString("nodeHandle"_s, elementID.value());
>         else
>             parameters->setBoolean("clipToViewport"_s, true);
>-        if (scrollIntoView.value_or(false))
>+        if (scrollIntoView.valueOr(false))
>             parameters->setBoolean("scrollIntoViewIfNeeded"_s, true);
>         m_host->sendCommandToBackend("takeScreenshot"_s, WTFMove(parameters), [protectedThis = makeRef(*this), completionHandler = WTFMove(completionHandler)](SessionHost::CommandResponse&& response) mutable {
>             if (response.isError || !response.responseObject) {
>diff --git a/Source/WebDriver/WebDriverService.cpp b/Source/WebDriver/WebDriverService.cpp
>index f04f4fdea80a6ab3c6cdc84b2e9f146d27171573..e526882c3ae3a13cb7aa78a1e98b158947b04424 100644
>--- a/Source/WebDriver/WebDriverService.cpp
>+++ b/Source/WebDriver/WebDriverService.cpp
>@@ -268,7 +268,7 @@ void WebDriverService::sendResponse(Function<void (HTTPRequestHandler::Response&
>         // Let body be a new JSON Object initialised with the following properties: "error", "message", "stacktrace".
>         auto errorObject = JSON::Object::create();
>         errorObject->setString("error"_s, result.errorString());
>-        errorObject->setString("message"_s, result.errorMessage().value_or(emptyString()));
>+        errorObject->setString("message"_s, result.errorMessage().valueOr(emptyString()));
>         errorObject->setString("stacktrace"_s, emptyString());
>         // If the error data dictionary contains any entries, set the "data" field on body to a new JSON Object populated with the dictionary.
>         if (auto& additionalData = result.additionalErrorData())
>@@ -695,12 +695,12 @@ void WebDriverService::createSession(Vector<Capabilities>&& capabilitiesList, st
>             resultObject->setString("sessionId"_s, m_session->id());
>             RefPtr<JSON::Object> capabilitiesObject = JSON::Object::create();
>             const auto& capabilities = m_session->capabilities();
>-            capabilitiesObject->setString("browserName"_s, capabilities.browserName.value_or(emptyString()));
>-            capabilitiesObject->setString("browserVersion"_s, capabilities.browserVersion.value_or(emptyString()));
>-            capabilitiesObject->setString("platformName"_s, capabilities.platformName.value_or(emptyString()));
>-            capabilitiesObject->setBoolean("acceptInsecureCerts"_s, capabilities.acceptInsecureCerts.value_or(false));
>-            capabilitiesObject->setBoolean("setWindowRect"_s, capabilities.setWindowRect.value_or(true));
>-            switch (capabilities.unhandledPromptBehavior.value_or(UnhandledPromptBehavior::DismissAndNotify)) {
>+            capabilitiesObject->setString("browserName"_s, capabilities.browserName.valueOr(emptyString()));
>+            capabilitiesObject->setString("browserVersion"_s, capabilities.browserVersion.valueOr(emptyString()));
>+            capabilitiesObject->setString("platformName"_s, capabilities.platformName.valueOr(emptyString()));
>+            capabilitiesObject->setBoolean("acceptInsecureCerts"_s, capabilities.acceptInsecureCerts.valueOr(false));
>+            capabilitiesObject->setBoolean("setWindowRect"_s, capabilities.setWindowRect.valueOr(true));
>+            switch (capabilities.unhandledPromptBehavior.valueOr(UnhandledPromptBehavior::DismissAndNotify)) {
>             case UnhandledPromptBehavior::Dismiss:
>                 capabilitiesObject->setString("unhandledPromptBehavior"_s, "dismiss");
>                 break;
>@@ -717,7 +717,7 @@ void WebDriverService::createSession(Vector<Capabilities>&& capabilitiesList, st
>                 capabilitiesObject->setString("unhandledPromptBehavior"_s, "ignore");
>                 break;
>             }
>-            switch (capabilities.pageLoadStrategy.value_or(PageLoadStrategy::Normal)) {
>+            switch (capabilities.pageLoadStrategy.valueOr(PageLoadStrategy::Normal)) {
>             case PageLoadStrategy::None:
>                 capabilitiesObject->setString("pageLoadStrategy"_s, "none");
>                 break;
>diff --git a/Source/WebKit/Shared/API/c/WKSecurityOriginRef.cpp b/Source/WebKit/Shared/API/c/WKSecurityOriginRef.cpp
>index 5e6be74b8da6d4b93603790ca4ad176d1f662c66..d07539b58be2e60ae0c0054d236bdbd5a4fbe714 100644
>--- a/Source/WebKit/Shared/API/c/WKSecurityOriginRef.cpp
>+++ b/Source/WebKit/Shared/API/c/WKSecurityOriginRef.cpp
>@@ -76,5 +76,5 @@ WKStringRef WKSecurityOriginCopyHost(WKSecurityOriginRef securityOrigin)
> 
> unsigned short WKSecurityOriginGetPort(WKSecurityOriginRef securityOrigin)
> {
>-    return WebKit::toImpl(securityOrigin)->securityOrigin().port().value_or(0);
>+    return WebKit::toImpl(securityOrigin)->securityOrigin().port().valueOr(0);
> }
>diff --git a/Source/WebKit/UIProcess/API/APIProcessPoolConfiguration.h b/Source/WebKit/UIProcess/API/APIProcessPoolConfiguration.h
>index 4ceba880bdd87faf9c5e41ac071f4efdcff60458..dad1c05c06158ee525a3e957af023b636a3d237d 100644
>--- a/Source/WebKit/UIProcess/API/APIProcessPoolConfiguration.h
>+++ b/Source/WebKit/UIProcess/API/APIProcessPoolConfiguration.h
>@@ -61,7 +61,7 @@ public:
> 
>     bool isAutomaticProcessWarmingEnabled() const
>     {
>-        return m_isAutomaticProcessWarmingEnabledByClient.value_or(m_clientWouldBenefitFromAutomaticProcessPrewarming);
>+        return m_isAutomaticProcessWarmingEnabledByClient.valueOr(m_clientWouldBenefitFromAutomaticProcessPrewarming);
>     }
> 
>     bool wasAutomaticProcessWarmingSetByClient() const { return !!m_isAutomaticProcessWarmingEnabledByClient; }
>@@ -157,7 +157,7 @@ public:
> 
>     bool processSwapsOnNavigation() const
>     {
>-        return m_processSwapsOnNavigationFromClient.value_or(m_processSwapsOnNavigationFromExperimentalFeatures);
>+        return m_processSwapsOnNavigationFromClient.valueOr(m_processSwapsOnNavigationFromExperimentalFeatures);
>     }
>     void setProcessSwapsOnNavigation(bool swaps) { m_processSwapsOnNavigationFromClient = swaps; }
>     void setProcessSwapsOnNavigationFromExperimentalFeatures(bool swaps) { m_processSwapsOnNavigationFromExperimentalFeatures = swaps; }
>diff --git a/Source/WebKit/UIProcess/API/Cocoa/WKSecurityOrigin.mm b/Source/WebKit/UIProcess/API/Cocoa/WKSecurityOrigin.mm
>index b7112cee17bdcc269bc9f9e271d2402da2166822..c5543a20b71e8c976e2122b9b4bea48b3751fc70 100644
>--- a/Source/WebKit/UIProcess/API/Cocoa/WKSecurityOrigin.mm
>+++ b/Source/WebKit/UIProcess/API/Cocoa/WKSecurityOrigin.mm
>@@ -58,7 +58,7 @@ - (NSString *)host
> 
> - (NSInteger)port
> {
>-    return _securityOrigin->securityOrigin().port().value_or(0);
>+    return _securityOrigin->securityOrigin().port().valueOr(0);
> }
> 
> #pragma mark WKObject protocol implementation
>diff --git a/Source/WebKit/UIProcess/API/Cocoa/WKWebViewConfiguration.mm b/Source/WebKit/UIProcess/API/Cocoa/WKWebViewConfiguration.mm
>index d287fd95bdc79bc9486c3ed4f836e6ec003203ec..9ad93fb6b419cec2c414056eb00bd15ba924ff6b 100644
>--- a/Source/WebKit/UIProcess/API/Cocoa/WKWebViewConfiguration.mm
>+++ b/Source/WebKit/UIProcess/API/Cocoa/WKWebViewConfiguration.mm
>@@ -946,7 +946,7 @@ - (void)_setCPULimit:(double)cpuLimit
> 
> - (double)_cpuLimit
> {
>-    return _pageConfiguration->cpuLimit().value_or(0);
>+    return _pageConfiguration->cpuLimit().valueOr(0);
> }
> 
> #endif // PLATFORM(MAC)
>diff --git a/Source/WebKit/UIProcess/API/glib/WebKitSecurityOrigin.cpp b/Source/WebKit/UIProcess/API/glib/WebKitSecurityOrigin.cpp
>index e4d065f918b3520818d906376ffca776693fc291..2e0789d4301f8a88159e8bee03067c156aa2f774 100644
>--- a/Source/WebKit/UIProcess/API/glib/WebKitSecurityOrigin.cpp
>+++ b/Source/WebKit/UIProcess/API/glib/WebKitSecurityOrigin.cpp
>@@ -217,7 +217,7 @@ guint16 webkit_security_origin_get_port(WebKitSecurityOrigin* origin)
> {
>     g_return_val_if_fail(origin, 0);
> 
>-    return origin->securityOrigin->port().value_or(0);
>+    return origin->securityOrigin->port().valueOr(0);
> }
> 
> /**
>diff --git a/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp b/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp
>index d7d0a6d49840af7124090b5b28458c0b02ce617d..d5fddab65618075a551862a055b9bad337bd5d85 100644
>--- a/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp
>+++ b/Source/WebKit/UIProcess/API/gtk/WebKitWebViewBase.cpp
>@@ -813,7 +813,7 @@ static void webkitWebViewBaseHandleWheelEvent(WebKitWebViewBase* webViewBase, Gd
>     WebKitWebViewBasePrivate* priv = webViewBase->priv;
>     ASSERT(!priv->dialog);
>     if (phase)
>-        priv->pageProxy->handleWheelEvent(NativeWebWheelEvent(event, phase.value(), momentum.value_or(WebWheelEvent::Phase::PhaseNone)));
>+        priv->pageProxy->handleWheelEvent(NativeWebWheelEvent(event, phase.value(), momentum.valueOr(WebWheelEvent::Phase::PhaseNone)));
>     else
>         priv->pageProxy->handleWheelEvent(NativeWebWheelEvent(event));
> }
>diff --git a/Source/WebKit/UIProcess/Automation/SimulatedInputDispatcher.cpp b/Source/WebKit/UIProcess/Automation/SimulatedInputDispatcher.cpp
>index dbe8397209da168db119baf460c5f2d8b695ff3f..0590c57b297df639d8465b64d5e872f04b3446b6 100644
>--- a/Source/WebKit/UIProcess/Automation/SimulatedInputDispatcher.cpp
>+++ b/Source/WebKit/UIProcess/Automation/SimulatedInputDispatcher.cpp
>@@ -59,7 +59,7 @@ Seconds SimulatedInputKeyFrame::maximumDuration() const
>     // The "compute the tick duration" algorithm (Â§17.4 Dispatching Actions).
>     Seconds result;
>     for (auto& entry : states)
>-        result = std::max(result, entry.second.duration.value_or(Seconds(0)));
>+        result = std::max(result, entry.second.duration.valueOr(Seconds(0)));
>     
>     return result;
> }
>@@ -259,7 +259,7 @@ void SimulatedInputDispatcher::transitionInputSourceToState(SimulatedInputSource
>         eventDispatchFinished(WTF::nullopt);
>         break;
>     case SimulatedInputSourceType::Mouse: {
>-        resolveLocation(a.location.value_or(WebCore::IntPoint()), b.location, b.origin.value_or(MouseMoveOrigin::Viewport), b.nodeHandle, [this, &a, &b, eventDispatchFinished = WTFMove(eventDispatchFinished)](Optional<WebCore::IntPoint> location, Optional<AutomationCommandError> error) mutable {
>+        resolveLocation(a.location.valueOr(WebCore::IntPoint()), b.location, b.origin.valueOr(MouseMoveOrigin::Viewport), b.nodeHandle, [this, &a, &b, eventDispatchFinished = WTFMove(eventDispatchFinished)](Optional<WebCore::IntPoint> location, Optional<AutomationCommandError> error) mutable {
>             if (error) {
>                 eventDispatchFinished(error);
>                 return;
>@@ -282,7 +282,7 @@ void SimulatedInputDispatcher::transitionInputSourceToState(SimulatedInputSource
>             } else if (a.location != b.location) {
>                 LOG(Automation, "SimulatedInputDispatcher[%p]: simulating MouseMove for transition to %d.%d", this, m_keyframeIndex, m_inputSourceStateIndex);
>                 // FIXME: This does not interpolate mousemoves per the "perform a pointer move" algorithm (Â§17.4 Dispatching Actions).
>-                m_client.simulateMouseInteraction(m_page, MouseInteraction::Move, b.pressedMouseButton.value_or(MouseButton::NoButton), b.location.value(), WTFMove(eventDispatchFinished));
>+                m_client.simulateMouseInteraction(m_page, MouseInteraction::Move, b.pressedMouseButton.valueOr(MouseButton::NoButton), b.location.value(), WTFMove(eventDispatchFinished));
>             } else
>                 eventDispatchFinished(WTF::nullopt);
>         });
>diff --git a/Source/WebKit/UIProcess/Automation/WebAutomationSession.cpp b/Source/WebKit/UIProcess/Automation/WebAutomationSession.cpp
>index 370b21ed6da03232aacaeb8204fcb657ae6b690a..57df5f3e0318103c42fb9dc9d0ddb1778b86a0eb 100644
>--- a/Source/WebKit/UIProcess/Automation/WebAutomationSession.cpp
>+++ b/Source/WebKit/UIProcess/Automation/WebAutomationSession.cpp
>@@ -387,7 +387,7 @@ void WebAutomationSession::setWindowFrameOfBrowsingContext(const String& handle,
>         this->restoreWindowForPage(webPage, [callback = WTFMove(callback), page = WTFMove(page), width, height, x, y]() mutable {
>             auto& webPage = *page;
>             webPage.getWindowFrameWithCallback([callback = WTFMove(callback), page = WTFMove(page), width, height, x, y](WebCore::FloatRect originalFrame) mutable {
>-                WebCore::FloatRect newFrame = WebCore::FloatRect(WebCore::FloatPoint(x.value_or(originalFrame.location().x()), y.value_or(originalFrame.location().y())), WebCore::FloatSize(width.value_or(originalFrame.size().width()), height.value_or(originalFrame.size().height())));
>+                WebCore::FloatRect newFrame = WebCore::FloatRect(WebCore::FloatPoint(x.valueOr(originalFrame.location().x()), y.valueOr(originalFrame.location().y())), WebCore::FloatSize(width.valueOr(originalFrame.size().width()), height.valueOr(originalFrame.size().height())));
>                 if (newFrame != originalFrame)
>                     page->setWindowFrame(newFrame);
>                 
>@@ -1834,7 +1834,7 @@ void WebAutomationSession::performInteractionSequence(const String& handle, cons
>             String pressedButtonString;
>             if (stateObject->getString("pressedButton"_s, pressedButtonString)) {
>                 auto protocolButton = Inspector::Protocol::AutomationHelpers::parseEnumValueFromString<Inspector::Protocol::Automation::MouseButton>(pressedButtonString);
>-                sourceState.pressedMouseButton = protocolMouseButtonToWebMouseEventButton(protocolButton.value_or(Inspector::Protocol::Automation::MouseButton::None));
>+                sourceState.pressedMouseButton = protocolMouseButtonToWebMouseEventButton(protocolButton.valueOr(Inspector::Protocol::Automation::MouseButton::None));
>             }
> 
>             String originString;
>diff --git a/Source/WebKit/UIProcess/Automation/WebAutomationSessionMacros.h b/Source/WebKit/UIProcess/Automation/WebAutomationSessionMacros.h
>index 3487fa9152f0428a60a2e27a96975d6480a74306..93af5abc708bd598f0f40bcc294852a3705297ae 100644
>--- a/Source/WebKit/UIProcess/Automation/WebAutomationSessionMacros.h
>+++ b/Source/WebKit/UIProcess/Automation/WebAutomationSessionMacros.h
>@@ -28,7 +28,7 @@
> #define errorNameAndDetailsSeparator ";"
> 
> // Make sure the predefined error name is valid, otherwise use InternalError.
>-#define VALIDATED_ERROR_MESSAGE(errorString) Inspector::Protocol::AutomationHelpers::parseEnumValueFromString<Inspector::Protocol::Automation::ErrorMessage>(errorString).value_or(Inspector::Protocol::Automation::ErrorMessage::InternalError)
>+#define VALIDATED_ERROR_MESSAGE(errorString) Inspector::Protocol::AutomationHelpers::parseEnumValueFromString<Inspector::Protocol::Automation::ErrorMessage>(errorString).valueOr(Inspector::Protocol::Automation::ErrorMessage::InternalError)
> 
> // If the error name is incorrect for these macros, it will be a compile-time error.
> #define STRING_FOR_PREDEFINED_ERROR_NAME(errorName) Inspector::Protocol::AutomationHelpers::getEnumConstantValue(Inspector::Protocol::Automation::ErrorMessage::errorName)
>diff --git a/Source/WebKit/UIProcess/ServiceWorkerProcessProxy.cpp b/Source/WebKit/UIProcess/ServiceWorkerProcessProxy.cpp
>index 86206bac9dbacad641c092f8324fd6df02eb92df..726883b3cf80f48f2dbfa563fc9bf7c55d57006f 100644
>--- a/Source/WebKit/UIProcess/ServiceWorkerProcessProxy.cpp
>+++ b/Source/WebKit/UIProcess/ServiceWorkerProcessProxy.cpp
>@@ -77,7 +77,7 @@ void ServiceWorkerProcessProxy::getLaunchOptions(ProcessLauncher::LaunchOptions&
> 
> void ServiceWorkerProcessProxy::start(const WebPreferencesStore& store, Optional<PAL::SessionID> initialSessionID)
> {
>-    send(Messages::WebProcess::EstablishWorkerContextConnectionToNetworkProcess { processPool().defaultPageGroup().pageGroupID(), m_serviceWorkerPageID, store, initialSessionID.value_or(PAL::SessionID::defaultSessionID()) }, 0);
>+    send(Messages::WebProcess::EstablishWorkerContextConnectionToNetworkProcess { processPool().defaultPageGroup().pageGroupID(), m_serviceWorkerPageID, store, initialSessionID.valueOr(PAL::SessionID::defaultSessionID()) }, 0);
> }
> 
> void ServiceWorkerProcessProxy::setUserAgent(const String& userAgent)
>diff --git a/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp b/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
>index b4e23994adfc6086725446c5b617db81bd10b673..73f55a4835f128831bc3288c8ad254370578c2f4 100644
>--- a/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
>+++ b/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
>@@ -224,7 +224,7 @@ void AuthenticatorManager::initTimeOutTimer(const Optional<unsigned>& timeOutInM
> {
>     using namespace AuthenticatorManagerInternal;
> 
>-    unsigned timeOutInMsValue = std::min(maxTimeOutValue, timeOutInMs.value_or(maxTimeOutValue));
>+    unsigned timeOutInMsValue = std::min(maxTimeOutValue, timeOutInMs.valueOr(maxTimeOutValue));
>     // FIXME(192061)
>     LOG_ERROR("Start timer. %d", timeOutInMsValue);
>     m_requestTimeOutTimer.startOneShot(Seconds::fromMilliseconds(timeOutInMsValue));
>diff --git a/Source/WebKit/UIProcess/WebPageProxy.cpp b/Source/WebKit/UIProcess/WebPageProxy.cpp
>index 4b01252ebb8fe927c5aaf4c570da8e455f8ecb6d..ab61fc24166cb6e4ed8ad51554de65d34aad7f96 100644
>--- a/Source/WebKit/UIProcess/WebPageProxy.cpp
>+++ b/Source/WebKit/UIProcess/WebPageProxy.cpp
>@@ -3056,7 +3056,7 @@ void WebPageProxy::windowScreenDidChange(PlatformDisplayID displayID)
> 
> float WebPageProxy::deviceScaleFactor() const
> {
>-    return m_customDeviceScaleFactor.value_or(m_intrinsicDeviceScaleFactor);
>+    return m_customDeviceScaleFactor.valueOr(m_intrinsicDeviceScaleFactor);
> }
> 
> void WebPageProxy::setCustomDeviceScaleFactor(float customScaleFactor)
>diff --git a/Source/WebKit/UIProcess/WebPageProxy.h b/Source/WebKit/UIProcess/WebPageProxy.h
>index ca5104885a46cef301ee6ab1f36bec81e3de62cb..a158b1f721ee2b0d9b1e4bd3fd42b09e6f513357 100644
>--- a/Source/WebKit/UIProcess/WebPageProxy.h
>+++ b/Source/WebKit/UIProcess/WebPageProxy.h
>@@ -1169,7 +1169,7 @@ public:
>     void setAutoSizingShouldExpandToViewHeight(bool);
> 
>     void setViewportSizeForCSSViewportUnits(const WebCore::IntSize&);
>-    WebCore::IntSize viewportSizeForCSSViewportUnits() const { return m_viewportSizeForCSSViewportUnits.value_or(WebCore::IntSize()); }
>+    WebCore::IntSize viewportSizeForCSSViewportUnits() const { return m_viewportSizeForCSSViewportUnits.valueOr(WebCore::IntSize()); }
> 
>     void didReceiveAuthenticationChallengeProxy(uint64_t frameID, Ref<AuthenticationChallengeProxy>&&);
> 
>diff --git a/Source/WebKit/UIProcess/gtk/WebPopupMenuProxyGtk.cpp b/Source/WebKit/UIProcess/gtk/WebPopupMenuProxyGtk.cpp
>index a6b1c9136a702c8335279d6d52fcf70b7dc660d9..e74601cd095d7724c16b2e45241df76f58223356 100644
>--- a/Source/WebKit/UIProcess/gtk/WebPopupMenuProxyGtk.cpp
>+++ b/Source/WebKit/UIProcess/gtk/WebPopupMenuProxyGtk.cpp
>@@ -69,7 +69,7 @@ void WebPopupMenuProxyGtk::selectItem(unsigned itemIndex)
> void WebPopupMenuProxyGtk::activateItem(Optional<unsigned> itemIndex)
> {
>     if (m_client)
>-        m_client->valueChangedForPopupMenu(this, itemIndex.value_or(m_selectedItem.value_or(-1)));
>+        m_client->valueChangedForPopupMenu(this, itemIndex.valueOr(m_selectedItem.valueOr(-1)));
> }
> 
> bool WebPopupMenuProxyGtk::activateItemAtPath(GtkTreePath* path)
>diff --git a/Source/WebKit/UIProcess/mac/LegacySessionStateCoding.cpp b/Source/WebKit/UIProcess/mac/LegacySessionStateCoding.cpp
>index 01c6069a7582be0f889afac044fcfa72e5e3df5a..ea6c3777e50136cca586c3740c7ca4b2966e9943 100644
>--- a/Source/WebKit/UIProcess/mac/LegacySessionStateCoding.cpp
>+++ b/Source/WebKit/UIProcess/mac/LegacySessionStateCoding.cpp
>@@ -284,8 +284,8 @@ static void encodeFormDataElement(HistoryEntryDataEncoder& encoder, const HTTPBo
>         encoder << false;
> 
>         encoder << element.fileStart;
>-        encoder << element.fileLength.value_or(-1);
>-        encoder << element.expectedFileModificationTime.value_or(WallTime::nan()).secondsSinceEpoch().value();
>+        encoder << element.fileLength.valueOr(-1);
>+        encoder << element.expectedFileModificationTime.valueOr(WallTime::nan()).secondsSinceEpoch().value();
>         break;
> 
>     case HTTPBody::Element::Type::Blob:
>diff --git a/Source/WebKit/WebProcess/Network/WebLoaderStrategy.cpp b/Source/WebKit/WebProcess/Network/WebLoaderStrategy.cpp
>index 1623b200908be20a26d90f2102a0a85e667a3379..3a40d206a01ebd9615a0208621bff6a55841f024 100644
>--- a/Source/WebKit/WebProcess/Network/WebLoaderStrategy.cpp
>+++ b/Source/WebKit/WebProcess/Network/WebLoaderStrategy.cpp
>@@ -156,8 +156,8 @@ void WebLoaderStrategy::scheduleLoad(ResourceLoader& resourceLoader, CachedResou
>     auto& frameLoaderClient = resourceLoader.frameLoader()->client();
> 
>     WebResourceLoader::TrackingParameters trackingParameters;
>-    trackingParameters.pageID = frameLoaderClient.pageID().value_or(0);
>-    trackingParameters.frameID = frameLoaderClient.frameID().value_or(0);
>+    trackingParameters.pageID = frameLoaderClient.pageID().valueOr(0);
>+    trackingParameters.frameID = frameLoaderClient.frameID().valueOr(0);
>     trackingParameters.resourceID = identifier;
>     auto sessionID = frameLoaderClient.sessionID();
> 
>diff --git a/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm b/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>index e88845740a88c66b31df7e2e4cd5268aca1c512c..c398ebe1995e468027bdaccd2ab49292d898d506 100644
>--- a/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>+++ b/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>@@ -1286,7 +1286,7 @@ IntPoint PDFPlugin::convertFromRootViewToPlugin(const IntPoint& point) const
> IntPoint PDFPlugin::convertFromPDFViewToRootView(const IntPoint& point) const
> {
>     IntPoint pointInPluginCoordinates(point.x(), size().height() - point.y());
>-    return m_rootViewToPluginTransform.inverse().value_or(AffineTransform()).mapPoint(pointInPluginCoordinates);
>+    return m_rootViewToPluginTransform.inverse().valueOr(AffineTransform()).mapPoint(pointInPluginCoordinates);
> }
>     
> IntPoint PDFPlugin::convertFromRootViewToPDFView(const IntPoint& point) const
>@@ -1315,7 +1315,7 @@ IntRect PDFPlugin::boundsOnScreen() const
>         return IntRect();
> 
>     FloatRect bounds = FloatRect(FloatPoint(), size());
>-    FloatRect rectInRootViewCoordinates = m_rootViewToPluginTransform.inverse().value_or(AffineTransform()).mapRect(bounds);
>+    FloatRect rectInRootViewCoordinates = m_rootViewToPluginTransform.inverse().valueOr(AffineTransform()).mapRect(bounds);
>     return frameView->contentsToScreen(enclosingIntRect(rectInRootViewCoordinates));
> }
> 
>@@ -1325,7 +1325,7 @@ void PDFPlugin::geometryDidChange(const IntSize& pluginSize, const IntRect&, con
>         return;
> 
>     m_size = pluginSize;
>-    m_rootViewToPluginTransform = pluginToRootViewTransform.inverse().value_or(AffineTransform());
>+    m_rootViewToPluginTransform = pluginToRootViewTransform.inverse().valueOr(AffineTransform());
>     [m_pdfLayerController setFrameSize:pluginSize];
> 
>     [CATransaction begin];
>diff --git a/Source/WebKit/WebProcess/WebCoreSupport/SessionStateConversion.cpp b/Source/WebKit/WebProcess/WebCoreSupport/SessionStateConversion.cpp
>index f283c728630ed4e424d6d0bdd4e2806e28234802..400d8325edee57c8f45c668f591f3eef0dd1f17c 100644
>--- a/Source/WebKit/WebProcess/WebCoreSupport/SessionStateConversion.cpp
>+++ b/Source/WebKit/WebProcess/WebCoreSupport/SessionStateConversion.cpp
>@@ -128,7 +128,7 @@ static Ref<FormData> toFormData(const HTTPBody& httpBody)
>             break;
> 
>         case HTTPBody::Element::Type::File:
>-            formData->appendFileRange(element.filePath, element.fileStart, element.fileLength.value_or(BlobDataItem::toEndOfFile), element.expectedFileModificationTime);
>+            formData->appendFileRange(element.filePath, element.fileStart, element.fileLength.valueOr(BlobDataItem::toEndOfFile), element.expectedFileModificationTime);
>             break;
> 
>         case HTTPBody::Element::Type::Blob:
>diff --git a/Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm b/Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm
>index 9f91731f43bfb11224757efb1017e4625c148f7f..c87b65953d7dc0d0f546727beb4d5bcd42addc57 100644
>--- a/Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm
>+++ b/Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm
>@@ -2992,7 +2992,7 @@ void WebPage::updateVisibleContentRects(const VisibleContentRectUpdateInfo& visi
>             m_oldestNonStableUpdateVisibleContentRectsTimestamp = oldestTimestamp;
>     }
> 
>-    float scaleToUse = scaleFromUIProcess.value_or(m_page->pageScaleFactor());
>+    float scaleToUse = scaleFromUIProcess.valueOr(m_page->pageScaleFactor());
>     FloatRect exposedContentRect = visibleContentRectUpdateInfo.exposedContentRect();
>     FloatRect adjustedExposedContentRect = adjustExposedRectForNewScale(exposedContentRect, visibleContentRectUpdateInfo.scale(), scaleToUse);
>     m_drawingArea->setExposedContentRect(adjustedExposedContentRect);
>diff --git a/Source/WebKit/WebProcess/WebPage/wpe/CompositingManager.cpp b/Source/WebKit/WebProcess/WebPage/wpe/CompositingManager.cpp
>index 9fb0104dee70616545846a2f21ae167cf682e5ba..d515a0b58eb82183c60176c703e2241ae2f8a832 100644
>--- a/Source/WebKit/WebProcess/WebPage/wpe/CompositingManager.cpp
>+++ b/Source/WebKit/WebProcess/WebPage/wpe/CompositingManager.cpp
>@@ -47,7 +47,7 @@ void CompositingManager::establishConnection(WebPage& webPage)
> 
> int CompositingManager::releaseConnectionFd()
> {
>-    int fd = m_connectionFd.value_or(-1);
>+    int fd = m_connectionFd.valueOr(-1);
>     m_connectionFd = WTF::nullopt;
>     return fd;
> }
>diff --git a/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm b/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>index 067f56cde3942c2ea71b1f4b52f871a5d4613cc5..b66948a19b538fd13714594e0c0de722780b4853 100644
>--- a/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>+++ b/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>@@ -88,7 +88,7 @@ - (NSString *)stringValue
> 
> - (unsigned short)port
> {
>-    return reinterpret_cast<SecurityOrigin*>(_private)->port().value_or(0);
>+    return reinterpret_cast<SecurityOrigin*>(_private)->port().valueOr(0);
> }
> 
> // FIXME: Overriding isEqual: without overriding hash will cause trouble if this ever goes into an NSSet or is the key in an NSDictionary,
>diff --git a/Source/WebKitLegacy/win/WebSecurityOrigin.cpp b/Source/WebKitLegacy/win/WebSecurityOrigin.cpp
>index 945b86923f6b1fca7d0b4777f0cd0600246a1000..57ca80e173dd9b5325f92f349fa894d1ae642684 100644
>--- a/Source/WebKitLegacy/win/WebSecurityOrigin.cpp
>+++ b/Source/WebKitLegacy/win/WebSecurityOrigin.cpp
>@@ -120,7 +120,7 @@ HRESULT WebSecurityOrigin::port(_Out_ unsigned short* result)
>     if (!result)
>         return E_POINTER;
> 
>-    *result = m_securityOrigin->port().value_or(0);
>+    *result = m_securityOrigin->port().valueOr(0);
> 
>     return S_OK;
> }
>diff --git a/Tools/ChangeLog b/Tools/ChangeLog
>index d069393c3432179af7494fd45c965f0e1e9adffe..1ead344e3bf9420f09c9db706e46060e7aad47a4 100644
>--- a/Tools/ChangeLog
>+++ b/Tools/ChangeLog
>@@ -1,3 +1,18 @@
>+2018-12-20  Chris Dumez  <cdumez@apple.com>
>+
>+        Use Optional::valueOr() instead of Optional::value_or()
>+        https://bugs.webkit.org/show_bug.cgi?id=192933
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * TestWebKitAPI/Tests/WTF/URLParser.cpp:
>+        (TestWebKitAPI::checkURL):
>+        (TestWebKitAPI::checkRelativeURL):
>+        (TestWebKitAPI::checkURLDifferences):
>+        (TestWebKitAPI::checkRelativeURLDifferences):
>+        * TestWebKitAPI/Tests/WebCore/URLParserTextEncoding.cpp:
>+        (TestWebKitAPI::checkURL):
>+
> 2018-12-19  Chris Dumez  <cdumez@apple.com>
> 
>         wtf/Optional.h: move-constructor and move-assignment operator should disengage the value being moved from
>diff --git a/Tools/TestWebKitAPI/Tests/WTF/URLParser.cpp b/Tools/TestWebKitAPI/Tests/WTF/URLParser.cpp
>index f8085d02dfe92aededadce5e57b941f6cd71a2d0..fb9fe64e3823e545c12f19c1ca00b037ef5f4171 100644
>--- a/Tools/TestWebKitAPI/Tests/WTF/URLParser.cpp
>+++ b/Tools/TestWebKitAPI/Tests/WTF/URLParser.cpp
>@@ -94,7 +94,7 @@ static void checkURL(const String& urlString, const ExpectedParts& parts, TestTa
>     EXPECT_TRUE(eq(parts.user, url.user()));
>     EXPECT_TRUE(eq(parts.password, url.pass()));
>     EXPECT_TRUE(eq(parts.host, url.host()));
>-    EXPECT_EQ(parts.port, url.port().value_or(0));
>+    EXPECT_EQ(parts.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(parts.path, url.path()));
>     EXPECT_TRUE(eq(parts.query, url.query()));
>     EXPECT_TRUE(eq(parts.fragment, url.fragmentIdentifier()));
>@@ -121,7 +121,7 @@ static void checkRelativeURL(const String& urlString, const String& baseURLStrin
>     EXPECT_TRUE(eq(parts.user, url.user()));
>     EXPECT_TRUE(eq(parts.password, url.pass()));
>     EXPECT_TRUE(eq(parts.host, url.host()));
>-    EXPECT_EQ(parts.port, url.port().value_or(0));
>+    EXPECT_EQ(parts.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(parts.path, url.path()));
>     EXPECT_TRUE(eq(parts.query, url.query()));
>     EXPECT_TRUE(eq(parts.fragment, url.fragmentIdentifier()));
>@@ -150,7 +150,7 @@ static void checkURLDifferences(const String& urlString, const ExpectedParts& pa
>     EXPECT_TRUE(eq(partsNew.user, url.user()));
>     EXPECT_TRUE(eq(partsNew.password, url.pass()));
>     EXPECT_TRUE(eq(partsNew.host, url.host()));
>-    EXPECT_EQ(partsNew.port, url.port().value_or(0));
>+    EXPECT_EQ(partsNew.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(partsNew.path, url.path()));
>     EXPECT_TRUE(eq(partsNew.query, url.query()));
>     EXPECT_TRUE(eq(partsNew.fragment, url.fragmentIdentifier()));
>@@ -179,7 +179,7 @@ static void checkRelativeURLDifferences(const String& urlString, const String& b
>     EXPECT_TRUE(eq(partsNew.user, url.user()));
>     EXPECT_TRUE(eq(partsNew.password, url.pass()));
>     EXPECT_TRUE(eq(partsNew.host, url.host()));
>-    EXPECT_EQ(partsNew.port, url.port().value_or(0));
>+    EXPECT_EQ(partsNew.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(partsNew.path, url.path()));
>     EXPECT_TRUE(eq(partsNew.query, url.query()));
>     EXPECT_TRUE(eq(partsNew.fragment, url.fragmentIdentifier()));
>diff --git a/Tools/TestWebKitAPI/Tests/WebCore/URLParserTextEncoding.cpp b/Tools/TestWebKitAPI/Tests/WebCore/URLParserTextEncoding.cpp
>index f892853d28b00a475a52c54adde9cb783d370f11..f6c3dea3b3cd96ac72d92581047363f6527f9886 100644
>--- a/Tools/TestWebKitAPI/Tests/WebCore/URLParserTextEncoding.cpp
>+++ b/Tools/TestWebKitAPI/Tests/WebCore/URLParserTextEncoding.cpp
>@@ -96,7 +96,7 @@ static void checkURL(const String& urlString, const TextEncoding* encoding, cons
>     EXPECT_TRUE(eq(parts.user, url.user()));
>     EXPECT_TRUE(eq(parts.password, url.pass()));
>     EXPECT_TRUE(eq(parts.host, url.host()));
>-    EXPECT_EQ(parts.port, url.port().value_or(0));
>+    EXPECT_EQ(parts.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(parts.path, url.path()));
>     EXPECT_TRUE(eq(parts.query, url.query()));
>     EXPECT_TRUE(eq(parts.fragment, url.fragmentIdentifier()));
>@@ -120,7 +120,7 @@ static void checkURL(const String& urlString, const String& baseURLString, const
>     EXPECT_TRUE(eq(parts.user, url.user()));
>     EXPECT_TRUE(eq(parts.password, url.pass()));
>     EXPECT_TRUE(eq(parts.host, url.host()));
>-    EXPECT_EQ(parts.port, url.port().value_or(0));
>+    EXPECT_EQ(parts.port, url.port().valueOr(0));
>     EXPECT_TRUE(eq(parts.path, url.path()));
>     EXPECT_TRUE(eq(parts.query, url.query()));
>     EXPECT_TRUE(eq(parts.fragment, url.fragmentIdentifier()));

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Attachments on bug 192933: 357817 | 357839