Attachment 372431 Details for Bug 196956 – [Patch] WIP

[patch] [Patch] WIP

196956.diff (text/plain), 120.23 KB, created by Devin Rousso on 2019-06-18 22:11:35 PDT

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Filename:

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Creator: Devin Rousso

Created: 2019-06-18 22:11:35 PDT

Size: 120.23 KB

patch

obsolete

>diff --git a/LayoutTests/http/tests/inspector/dom/disconnect-dom-tree-after-main-frame-navigation.html b/LayoutTests/http/tests/inspector/dom/disconnect-dom-tree-after-main-frame-navigation.html
>index 6f5475e34aa..de6e2973577 100644
>--- a/LayoutTests/http/tests/inspector/dom/disconnect-dom-tree-after-main-frame-navigation.html
>+++ b/LayoutTests/http/tests/inspector/dom/disconnect-dom-tree-after-main-frame-navigation.html
>@@ -11,7 +11,7 @@ function test()
>         name: "CheckLazyInitializationOfDOMTree",
>         description: "Check that DOMTree instances are created lazily.",
>         test(resolve, reject) {
>-            let instances = WI.domManager.retainedObjectsWithPrototype(WI.DOMTree);
>+            let instances = WI.domManager.activelyListeningObjectsWithPrototype(WI.DOMTree);
>             InspectorTest.expectThat(instances.size === 0, "There should not be a DOMTree listening to DOMTreeManager events initially.");
>             InspectorTest.log("DOMTree instance count: " + instances.size);
>             resolve();
>@@ -25,7 +25,7 @@ function test()
>             let mainFrame = WI.networkManager.mainFrame;
>             mainFrame.domTree; // Force creation of the root DOM tree.
> 
>-            let instances = WI.domManager.retainedObjectsWithPrototype(WI.DOMTree);
>+            let instances = WI.domManager.activelyListeningObjectsWithPrototype(WI.DOMTree);
>             InspectorTest.expectThat(instances.size === 1, "There should be a one DOMTree listening to DOMTreeManager events after creation.");
>             InspectorTest.log("DOMTree instance count: " + instances.size);
> 
>@@ -39,7 +39,7 @@ function test()
>             let childrenLevel3 = Array.from(childrenLevel2[0].childFrameCollection);
>             childrenLevel3[0].domTree;
> 
>-            instances = WI.domManager.retainedObjectsWithPrototype(WI.DOMTree);
>+            instances = WI.domManager.activelyListeningObjectsWithPrototype(WI.DOMTree);
>             InspectorTest.expectThat(instances.size === 4, "There should be four DOMTrees listening to DOMTreeManager events after touching each Frame.");
>             InspectorTest.log("DOMTree instance count: " + instances.size);
> 
>@@ -53,7 +53,7 @@ function test()
>         test(resolve, reject) {
>             WI.Frame.awaitEvent(WI.Frame.Event.MainResourceDidChange)
>             .then((event) => {
>-                let instances = WI.domManager.retainedObjectsWithPrototype(WI.DOMTree);
>+                let instances = WI.domManager.activelyListeningObjectsWithPrototype(WI.DOMTree);
>                 InspectorTest.expectThat(instances.size === 0, "There should not be any DOMTrees listening to DOMTreeManager events after a main frame navigation.");
>                 InspectorTest.log("DOMTree instance count: " + instances.size);
>             })
>diff --git a/LayoutTests/inspector/unit-tests/linked-list-expected.txt b/LayoutTests/inspector/unit-tests/linked-list-expected.txt
>deleted file mode 100644
>index 865e1007d05..00000000000
>--- a/LayoutTests/inspector/unit-tests/linked-list-expected.txt
>+++ /dev/null
>@@ -1,25 +0,0 @@
>-Testing all methods of LinkedList.
>-
>-
>-== Running test suite: LinkedList
>--- Running test case: Adding items
>-0
>-[]
>-2
>-["one","two"]
>-3
>-["one","two","three"]
>-
>--- Running test case: Removing items
>-3
>-["one","two","three"]
>-2
>-["one","three"]
>-
>--- Running test case: Removing all items
>-0
>-[]
>-
>--- Running test case: Iterating using forEach method
>-["one","two","three"]
>-
>diff --git a/LayoutTests/inspector/unit-tests/linked-list.html b/LayoutTests/inspector/unit-tests/linked-list.html
>deleted file mode 100644
>index c803257647a..00000000000
>--- a/LayoutTests/inspector/unit-tests/linked-list.html
>+++ /dev/null
>@@ -1,92 +0,0 @@
>-<!doctype html>
>-<html>
>-<head>
>-<script src="../../http/tests/inspector/resources/inspector-test.js"></script>
>-<script>
>-function test()
>-{
>-    let suite = InspectorTest.createAsyncSuite("LinkedList");
>-
>-    suite.addTestCase({
>-        name: "Adding items",
>-        test(resolve, reject) {
>-            let list = new LinkedList;
>-
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            list.push("one");
>-            list.push("two");
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            list.push("three");
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Removing items",
>-        test(resolve, reject) {
>-            let list = new LinkedList;
>-
>-            list.push("one");
>-            let nodeTwo = list.push("two");
>-            list.push("three");
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            list.remove(nodeTwo);
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Removing all items",
>-        test(resolve, reject) {
>-            let list = new LinkedList;
>-
>-            list.push("one");
>-            list.push("two");
>-            list.push("three");
>-            list.clear();
>-            InspectorTest.log(list.length);
>-            InspectorTest.log(list);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Iterating using forEach method",
>-        test(resolve, reject) {
>-            let list = new LinkedList;
>-
>-            list.push("one");
>-            list.push("two");
>-            list.push("three");
>-
>-            let values = [];
>-            list.forEach(function(value) {
>-                values.push(value);
>-            });
>-            InspectorTest.log(values);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.runTestCasesAndFinish();
>-}
>-</script>
>-</head>
>-<body onload="runTest()">
>-    <p>Testing all methods of LinkedList.</p>
>-</body>
>-</html>
>diff --git a/LayoutTests/inspector/unit-tests/list-multimap-expected.txt b/LayoutTests/inspector/unit-tests/list-multimap-expected.txt
>deleted file mode 100644
>index 7bf5fed1842..00000000000
>--- a/LayoutTests/inspector/unit-tests/list-multimap-expected.txt
>+++ /dev/null
>@@ -1,56 +0,0 @@
>-Testing all methods of ListMultimap.
>-
>-
>-== Running test suite: ListMultimap
>--- Running test case: Instantiating Multimap
>-0
>-[]
>-
>--- Running test case: Adding unique keys and values
>-2
>-[["zero","one"],["two","three"]]
>-
>--- Running test case: Adding repeating keys and unique values
>-2
>-[["zero","one"],["zero","two"]]
>-
>--- Running test case: Adding unique keys and repeating values
>-3
>-[["zero","one"],["two","one"],["three","one"]]
>-
>--- Running test case: Adding repeating keys and values
>-3
>-[["zero","one"],["two","one"],["zero","three"]]
>-
>--- Running test case: Deleting existing keys and values
>-PASS: The key and the value were successfully deleted.
>-1
>-[[2,3]]
>-PASS: The key and the value were successfully deleted.
>-0
>-[]
>-
>--- Running test case: Deleting non-existing keys and non-existing values
>-PASS: Nothing was removed.
>-PASS: Nothing was removed.
>-PASS: Nothing was removed.
>-PASS: Nothing was removed.
>-PASS: Nothing was removed.
>-3
>-[[0,1],[2,3],[4,4]]
>-
>--- Running test case: Deleting values for given key
>-PASS: Nothing was removed.
>-3
>-[["opossum","badger"],["opossum","raccoon"],["raccoon","opossum"]]
>-PASS: Values were removed.
>-1
>-[["raccoon","opossum"]]
>-
>--- Running test case: Deleting all keys and values
>-0
>-[]
>-
>--- Running test case: Iterating using forEach method
>-[["Platypus","Sugar glider"],["Quoll","Wallaby"]]
>-
>diff --git a/LayoutTests/inspector/unit-tests/list-multimap.html b/LayoutTests/inspector/unit-tests/list-multimap.html
>deleted file mode 100644
>index 465542228c4..00000000000
>--- a/LayoutTests/inspector/unit-tests/list-multimap.html
>+++ /dev/null
>@@ -1,191 +0,0 @@
>-<!doctype html>
>-<html>
>-<head>
>-<script src="../../http/tests/inspector/resources/inspector-test.js"></script>
>-<script>
>-function test()
>-{
>-    let suite = InspectorTest.createAsyncSuite("ListMultimap");
>-
>-    suite.addTestCase({
>-        name: "Instantiating Multimap",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Adding unique keys and values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add("zero", "one");
>-            multimap.add("two", "three");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Adding repeating keys and unique values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add("zero", "one");
>-            multimap.add("zero", "two");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Adding unique keys and repeating values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add("zero", "one");
>-            multimap.add("two", "one");
>-            multimap.add("three", "one");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Adding repeating keys and values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add("zero", "one");
>-            multimap.add("two", "one");
>-            multimap.add("zero", "one");
>-            multimap.add("zero", "three");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Deleting existing keys and values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add(0, 1);
>-            multimap.add(2, 3);
>-            multimap.add(2, 3);
>-
>-            InspectorTest.expectThat(multimap.delete(0, 1), "The key and the value were successfully deleted.");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            InspectorTest.expectThat(multimap.delete(2, 3), "The key and the value were successfully deleted.");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Deleting non-existing keys and non-existing values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add(0, 1);
>-            multimap.add(2, 3);
>-            multimap.add(4, 4);
>-
>-            InspectorTest.expectThat(!multimap.delete(0, 3), "Nothing was removed.");
>-            InspectorTest.expectThat(!multimap.delete(2, 1), "Nothing was removed.");
>-            InspectorTest.expectThat(!multimap.delete(3, 0), "Nothing was removed.");
>-            InspectorTest.expectThat(!multimap.delete(4, 3), "Nothing was removed.");
>-            InspectorTest.expectThat(!multimap.delete(0, 4), "Nothing was removed.");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Deleting values for given key",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-
>-            multimap.add("opossum", "badger");
>-            multimap.add("opossum", "raccoon");
>-            multimap.add("raccoon", "opossum");
>-
>-            InspectorTest.expectThat(!multimap.deleteAll("badger"), "Nothing was removed.");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            InspectorTest.expectThat(multimap.deleteAll("opossum"), "Values were removed.");
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Deleting all keys and values",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-            multimap.add("badger", "raccoon");
>-            multimap.clear();
>-
>-            InspectorTest.log(multimap.size);
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.addTestCase({
>-        name: "Iterating using forEach method",
>-        test(resolve, reject) {
>-            let multimap = new ListMultimap;
>-            multimap.add("Platypus", "Sugar glider");
>-            multimap.add("Quoll", "Wallaby");
>-
>-            let list = [];
>-            multimap.forEach(function(pair) {
>-                list.push(pair);
>-            });
>-            InspectorTest.log(multimap);
>-
>-            resolve();
>-        }
>-    });
>-
>-    suite.runTestCasesAndFinish();
>-}
>-</script>
>-</head>
>-<body onload="runTest()">
>-    <p>Testing all methods of ListMultimap.</p>
>-</body>
>-</html>
>diff --git a/Source/JavaScriptCore/CMakeLists.txt b/Source/JavaScriptCore/CMakeLists.txt
>index d8f36400fd8..1121a993267 100644
>--- a/Source/JavaScriptCore/CMakeLists.txt
>+++ b/Source/JavaScriptCore/CMakeLists.txt
>@@ -638,6 +638,7 @@ set(JavaScriptCore_PRIVATE_FRAMEWORK_HEADERS
>     inspector/InspectorFrontendRouter.h
>     inspector/InspectorProtocolTypes.h
>     inspector/InspectorTarget.h
>+    inspector/InspectorUtilities.h
>     inspector/PerGlobalObjectWrapperWorld.h
>     inspector/ScriptArguments.h
>     inspector/ScriptBreakpoint.h
>diff --git a/Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj b/Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
>index 6750a65b6e3..f342f48b81f 100644
>--- a/Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
>+++ b/Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
>@@ -1273,6 +1273,7 @@
> 		9064337DD4B0402BAF34A592 /* JSScriptFetcher.h in Headers */ = {isa = PBXBuildFile; fileRef = 6BA93C9590484C5BAD9316EA /* JSScriptFetcher.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		91278D5521DEB82600B57184 /* InspectorAuditAgent.h in Headers */ = {isa = PBXBuildFile; fileRef = 91278D5321DEB82500B57184 /* InspectorAuditAgent.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		91278D5821DEDA9600B57184 /* JSGlobalObjectAuditAgent.h in Headers */ = {isa = PBXBuildFile; fileRef = 91278D5621DEDA9400B57184 /* JSGlobalObjectAuditAgent.h */; };
>+		91E82B73226588FA0033E9E0 /* InspectorUtilities.h in Headers */ = {isa = PBXBuildFile; fileRef = 91E82B71226588F90033E9E0 /* InspectorUtilities.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		93052C350FB792190048FDC3 /* ParserArena.h in Headers */ = {isa = PBXBuildFile; fileRef = 93052C330FB792190048FDC3 /* ParserArena.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		932F5BD30822A1C700736975 /* CoreFoundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6560A4CF04B3B3E7008AE952 /* CoreFoundation.framework */; };
> 		932F5BD60822A1C700736975 /* libobjc.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = 51F0EC0705C86C9A00E6DF1B /* libobjc.dylib */; };
>@@ -4038,6 +4039,8 @@
> 		91278D5321DEB82500B57184 /* InspectorAuditAgent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InspectorAuditAgent.h; sourceTree = "<group>"; };
> 		91278D5621DEDA9400B57184 /* JSGlobalObjectAuditAgent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JSGlobalObjectAuditAgent.h; sourceTree = "<group>"; };
> 		91278D5721DEDA9500B57184 /* JSGlobalObjectAuditAgent.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = JSGlobalObjectAuditAgent.cpp; sourceTree = "<group>"; };
>+		91E82B70226588F90033E9E0 /* InspectorUtilities.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = InspectorUtilities.cpp; sourceTree = "<group>"; };
>+		91E82B71226588F90033E9E0 /* InspectorUtilities.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InspectorUtilities.h; sourceTree = "<group>"; };
> 		93052C320FB792190048FDC3 /* ParserArena.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ParserArena.cpp; sourceTree = "<group>"; };
> 		93052C330FB792190048FDC3 /* ParserArena.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ParserArena.h; sourceTree = "<group>"; };
> 		930DAD030FB1EB1A0082D205 /* NodeConstructors.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = NodeConstructors.h; sourceTree = "<group>"; };
>@@ -8236,6 +8239,8 @@
> 				99F1A7001B98FBEC00463B26 /* InspectorFrontendRouter.h */,
> 				A55D93AB18514F7900400DED /* InspectorProtocolTypes.h */,
> 				A555FF382159D2D600FCD826 /* InspectorTarget.h */,
>+				91E82B70226588F90033E9E0 /* InspectorUtilities.cpp */,
>+				91E82B71226588F90033E9E0 /* InspectorUtilities.h */,
> 				A503FA13188E0FAF00110F14 /* JavaScriptCallFrame.cpp */,
> 				A503FA14188E0FAF00110F14 /* JavaScriptCallFrame.h */,
> 				A5C3A1A318C0490200C9593A /* JSGlobalObjectConsoleClient.cpp */,
>@@ -9321,6 +9326,7 @@
> 				A55165D31BDF0B9E003B75C1 /* InspectorScriptProfilerAgent.h in Headers */,
> 				A555FF3B2159D2F500FCD826 /* InspectorTarget.h in Headers */,
> 				A52C95FF2159D432007D8AC0 /* InspectorTargetAgent.h in Headers */,
>+				91E82B73226588FA0033E9E0 /* InspectorUtilities.h in Headers */,
> 				0F49E9AA20AB4D00001CA0AA /* InstanceOfAccessCase.h in Headers */,
> 				0FB399BF20AF6B3F0017E213 /* InstanceOfStatus.h in Headers */,
> 				0FB399C020AF6B430017E213 /* InstanceOfVariant.h in Headers */,
>diff --git a/Source/JavaScriptCore/Sources.txt b/Source/JavaScriptCore/Sources.txt
>index b8893ba8fcb..755e0d7a4e0 100644
>--- a/Source/JavaScriptCore/Sources.txt
>+++ b/Source/JavaScriptCore/Sources.txt
>@@ -563,6 +563,7 @@ inspector/InjectedScriptModule.cpp
> inspector/InspectorAgentRegistry.cpp
> inspector/InspectorFrontendRouter.cpp
> inspector/InspectorBackendDispatcher.cpp
>+inspector/InspectorUtilities.cpp
> inspector/JSGlobalObjectConsoleClient.cpp
> inspector/JSGlobalObjectInspectorController.cpp
> inspector/JSGlobalObjectScriptDebugServer.cpp
>diff --git a/Source/JavaScriptCore/inspector/InspectorUtilities.cpp b/Source/JavaScriptCore/inspector/InspectorUtilities.cpp
>new file mode 100644
>index 00000000000..5b062787326
>--- /dev/null
>+++ b/Source/JavaScriptCore/inspector/InspectorUtilities.cpp
>@@ -0,0 +1,113 @@
>+/*
>+ * Copyright (C) 2019 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
>+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
>+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
>+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
>+ * THE POSSIBILITY OF SUCH DAMAGE.
>+ */
>+
>+#include "config.h"
>+#include "InspectorUtilities.h"
>+
>+#include "JSWeakMap.h"
>+#include "JSWeakSet.h"
>+
>+namespace Inspector {
>+
>+namespace InspectorUtilities {
>+
>+using namespace JSC;
>+
>+Optional<unsigned> weakMapSize(JSC::ExecState& exec)
>+{
>+    if (exec.argumentCount() < 1)
>+        return WTF::nullopt;
>+
>+    VM& vm = exec.vm();
>+    auto* weakMap = jsDynamicCast<JSWeakMap*>(vm, exec.uncheckedArgument(0));
>+    if (!weakMap)
>+        return WTF::nullopt;
>+
>+    return weakMap->size();
>+}
>+
>+Optional<JSC::JSValue> weakMapEntries(JSC::ExecState& exec, unsigned numberToFetch, const Function<JSC::JSValue(JSC::JSValue, JSC::JSValue)>& mapFunction)
>+{
>+    VM& vm = exec.vm();
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+    auto* weakMap = jsDynamicCast<JSWeakMap*>(vm, exec.uncheckedArgument(0));
>+    if (!weakMap)
>+        return WTF::nullopt;
>+
>+    auto* array = constructEmptyArray(&exec, nullptr);
>+    RETURN_IF_EXCEPTION(scope, WTF::nullopt);
>+
>+    MarkedArgumentBuffer buffer;
>+    weakMap->takeSnapshot(buffer, numberToFetch);
>+    for (unsigned index = 0; index < buffer.size(); index += 2) {
>+        auto key = buffer.at(index);
>+        auto value = buffer.at(index + 1);
>+        array->putDirectIndex(&exec, index / 2, mapFunction(key, value));
>+        RETURN_IF_EXCEPTION(scope, WTF::nullopt);
>+    }
>+
>+    return JSValue(array);
>+}
>+
>+Optional<unsigned> weakSetSize(JSC::ExecState& exec)
>+{
>+    if (exec.argumentCount() < 1)
>+        return WTF::nullopt;
>+
>+    VM& vm = exec.vm();
>+    auto* weakSet = jsDynamicCast<JSWeakSet*>(vm, exec.uncheckedArgument(0));
>+    if (!weakSet)
>+        return WTF::nullopt;
>+
>+    return weakSet->size();
>+}
>+
>+Optional<JSC::JSValue> weakSetEntries(JSC::ExecState& exec, unsigned numberToFetch, const Function<JSC::JSValue(JSC::JSValue)>& mapFunction)
>+{
>+    VM& vm = exec.vm();
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+    auto* weakSet = jsDynamicCast<JSWeakSet*>(vm, exec.uncheckedArgument(0));
>+    if (!weakSet)
>+        return WTF::nullopt;
>+
>+    auto* array = constructEmptyArray(&exec, nullptr);
>+    RETURN_IF_EXCEPTION(scope, WTF::nullopt);
>+
>+    MarkedArgumentBuffer buffer;
>+    weakSet->takeSnapshot(buffer, numberToFetch);
>+    for (unsigned index = 0; index < buffer.size(); ++index) {
>+        auto value = buffer.at(index);
>+        array->putDirectIndex(&exec, index, mapFunction(value));
>+        RETURN_IF_EXCEPTION(scope, WTF::nullopt);
>+    }
>+
>+    return JSValue(array);
>+}
>+
>+} // namespace InspectorUtilities
>+
>+} // namespace Inspector
>diff --git a/Source/JavaScriptCore/inspector/InspectorUtilities.h b/Source/JavaScriptCore/inspector/InspectorUtilities.h
>new file mode 100644
>index 00000000000..4e1b36b8a42
>--- /dev/null
>+++ b/Source/JavaScriptCore/inspector/InspectorUtilities.h
>@@ -0,0 +1,43 @@
>+/*
>+ * Copyright (C) 2019 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
>+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
>+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
>+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
>+ * THE POSSIBILITY OF SUCH DAMAGE.
>+ */
>+
>+#pragma once
>+
>+#include "JSCInlines.h"
>+#include <wtf/Function.h>
>+#include <wtf/Optional.h>
>+
>+namespace Inspector {
>+
>+namespace InspectorUtilities {
>+
>+JS_EXPORT_PRIVATE Optional<unsigned> weakMapSize(JSC::ExecState&);
>+JS_EXPORT_PRIVATE Optional<JSC::JSValue> weakMapEntries(JSC::ExecState&, unsigned numberToFetch, const Function<JSC::JSValue(JSC::JSValue, JSC::JSValue)>& mapFunction);
>+JS_EXPORT_PRIVATE Optional<unsigned> weakSetSize(JSC::ExecState&);
>+JS_EXPORT_PRIVATE Optional<JSC::JSValue> weakSetEntries(JSC::ExecState&, unsigned numberToFetch, const Function<JSC::JSValue(JSC::JSValue)>& mapFunction);
>+
>+} // namespace InspectorUtilities
>+
>+} // namespace Inspector
>diff --git a/Source/JavaScriptCore/inspector/JSInjectedScriptHost.cpp b/Source/JavaScriptCore/inspector/JSInjectedScriptHost.cpp
>index d9725c0d8f4..4655ed3cdf4 100644
>--- a/Source/JavaScriptCore/inspector/JSInjectedScriptHost.cpp
>+++ b/Source/JavaScriptCore/inspector/JSInjectedScriptHost.cpp
>@@ -36,6 +36,7 @@
> #include "FunctionPrototype.h"
> #include "HeapIterationScope.h"
> #include "InjectedScriptHost.h"
>+#include "InspectorUtilities.h"
> #include "IterationKind.h"
> #include "IteratorOperations.h"
> #include "IteratorPrototype.h"
>@@ -444,30 +445,14 @@ JSValue JSInjectedScriptHost::proxyTargetValue(ExecState *exec)
> 
> JSValue JSInjectedScriptHost::weakMapSize(ExecState* exec)
> {
>-    if (exec->argumentCount() < 1)
>+    auto size = InspectorUtilities::weakMapSize(*exec);
>+    if (!size)
>         return jsUndefined();
>-
>-    VM& vm = exec->vm();
>-    JSValue value = exec->uncheckedArgument(0);
>-    JSWeakMap* weakMap = jsDynamicCast<JSWeakMap*>(vm, value);
>-    if (!weakMap)
>-        return jsUndefined();
>-
>-    return jsNumber(weakMap->size());
>+    return jsNumber(size.value());
> }
> 
> JSValue JSInjectedScriptHost::weakMapEntries(ExecState* exec)
> {
>-    if (exec->argumentCount() < 1)
>-        return jsUndefined();
>-
>-    VM& vm = exec->vm();
>-    auto scope = DECLARE_THROW_SCOPE(vm);
>-    JSValue value = exec->uncheckedArgument(0);
>-    JSWeakMap* weakMap = jsDynamicCast<JSWeakMap*>(vm, value);
>-    if (!weakMap)
>-        return jsUndefined();
>-
>     unsigned numberToFetch = 100;
> 
>     JSValue numberToFetchArg = exec->argument(1);
>@@ -475,49 +460,27 @@ JSValue JSInjectedScriptHost::weakMapEntries(ExecState* exec)
>     if (fetchDouble >= 0)
>         numberToFetch = static_cast<unsigned>(fetchDouble);
> 
>-    JSArray* array = constructEmptyArray(exec, nullptr);
>-    RETURN_IF_EXCEPTION(scope, JSValue());
>-
>-    MarkedArgumentBuffer buffer;
>-    weakMap->takeSnapshot(buffer, numberToFetch);
>-
>-    for (unsigned index = 0; index < buffer.size(); index += 2) {
>-        JSObject* entry = constructEmptyObject(exec);
>-        entry->putDirect(vm, Identifier::fromString(exec, "key"), buffer.at(index));
>-        entry->putDirect(vm, Identifier::fromString(exec, "value"), buffer.at(index + 1));
>-        array->putDirectIndex(exec, index / 2, entry);
>-        RETURN_IF_EXCEPTION(scope, JSValue());
>-    }
>-
>-    return array;
>+    auto entries = InspectorUtilities::weakMapEntries(*exec, numberToFetch, [&] (JSValue key, JSValue value) {
>+        auto* entry = constructEmptyObject(exec);
>+        entry->putDirect(exec->vm(), Identifier::fromString(exec, "key"), key);
>+        entry->putDirect(exec->vm(), Identifier::fromString(exec, "value"), value);
>+        return entry;
>+    });
>+    if (!entries)
>+        return jsUndefined();
>+    return entries.value();
> }
> 
> JSValue JSInjectedScriptHost::weakSetSize(ExecState* exec)
> {
>-    if (exec->argumentCount() < 1)
>+    auto size = InspectorUtilities::weakSetSize(*exec);
>+    if (!size)
>         return jsUndefined();
>-
>-    VM& vm = exec->vm();
>-    JSValue value = exec->uncheckedArgument(0);
>-    JSWeakSet* weakSet = jsDynamicCast<JSWeakSet*>(vm, value);
>-    if (!weakSet)
>-        return jsUndefined();
>-
>-    return jsNumber(weakSet->size());
>+    return jsNumber(size.value());
> }
> 
> JSValue JSInjectedScriptHost::weakSetEntries(ExecState* exec)
> {
>-    if (exec->argumentCount() < 1)
>-        return jsUndefined();
>-
>-    VM& vm = exec->vm();
>-    auto scope = DECLARE_THROW_SCOPE(vm);
>-    JSValue value = exec->uncheckedArgument(0);
>-    JSWeakSet* weakSet = jsDynamicCast<JSWeakSet*>(vm, value);
>-    if (!weakSet)
>-        return jsUndefined();
>-
>     unsigned numberToFetch = 100;
> 
>     JSValue numberToFetchArg = exec->argument(1);
>@@ -525,20 +488,14 @@ JSValue JSInjectedScriptHost::weakSetEntries(ExecState* exec)
>     if (fetchDouble >= 0)
>         numberToFetch = static_cast<unsigned>(fetchDouble);
> 
>-    JSArray* array = constructEmptyArray(exec, nullptr);
>-    RETURN_IF_EXCEPTION(scope, JSValue());
>-
>-    MarkedArgumentBuffer buffer;
>-    weakSet->takeSnapshot(buffer, numberToFetch);
>-
>-    for (unsigned index = 0; index < buffer.size(); ++index) {
>-        JSObject* entry = constructEmptyObject(exec);
>-        entry->putDirect(vm, Identifier::fromString(exec, "value"), buffer.at(index));
>-        array->putDirectIndex(exec, index, entry);
>-        RETURN_IF_EXCEPTION(scope, JSValue());
>-    }
>-
>-    return array;
>+    auto entries = InspectorUtilities::weakSetEntries(*exec, numberToFetch, [&] (JSValue value) {
>+        auto* entry = constructEmptyObject(exec);
>+        entry->putDirect(exec->vm(), Identifier::fromString(exec, "value"), value);
>+        return entry;
>+    });
>+    if (!entries)
>+        return jsUndefined();
>+    return entries.value();
> }
> 
> static JSObject* cloneArrayIteratorObject(ExecState* exec, VM& vm, JSObject* iteratorObject, JSGlobalObject* globalObject, JSValue nextIndex, JSValue iteratedObject)
>diff --git a/Source/WebCore/inspector/InspectorFrontendHost.cpp b/Source/WebCore/inspector/InspectorFrontendHost.cpp
>index 71ca44bffd4..b6068e04781 100644
>--- a/Source/WebCore/inspector/InspectorFrontendHost.cpp
>+++ b/Source/WebCore/inspector/InspectorFrontendHost.cpp
>@@ -55,6 +55,7 @@
> #include "Pasteboard.h"
> #include "ScriptState.h"
> #include "UserGestureIndicator.h"
>+#include <JavaScriptCore/InspectorUtilities.h>
> #include <JavaScriptCore/ScriptFunctionCall.h>
> #include <pal/system/Sound.h>
> #include <wtf/StdLibExtras.h>
>@@ -464,6 +465,45 @@ bool InspectorFrontendHost::isBeingInspected()
>     return inspectorController.hasLocalFrontend() || inspectorController.hasRemoteFrontend();
> }
> 
>+ExceptionOr<unsigned> InspectorFrontendHost::weakMapSize(JSC::ExecState& exec)
>+{
>+    auto size = InspectorUtilities::weakMapSize(exec);
>+    if (!size)
>+        return Exception { TypeError, "Argument 1 ('weakMap') to InspectorFrontendHost.weakMapSize must be an instance of WeakMap"_s };
>+    return size.value();
>+}
>+
>+ExceptionOr<JSC::JSValue> InspectorFrontendHost::weakMapEntries(JSC::ExecState& exec)
>+{
>+    auto entries = InspectorUtilities::weakMapEntries(exec, 0, [&] (JSC::JSValue key, JSC::JSValue value) {
>+        auto* array = constructEmptyArray(&exec, nullptr);
>+        array->putDirectIndex(&exec, array->length(), key);
>+        array->putDirectIndex(&exec, array->length(), value);
>+        return array;
>+    });
>+    if (!entries)
>+        return Exception { TypeError, "Argument 1 ('weakMap') to InspectorFrontendHost.weakMapEntries must be an instance of WeakMap"_s };
>+    return WTFMove(entries.value());
>+}
>+
>+ExceptionOr<unsigned> InspectorFrontendHost::weakSetSize(JSC::ExecState& exec)
>+{
>+    auto size = InspectorUtilities::weakSetSize(exec);
>+    if (!size)
>+        return Exception { TypeError, "Argument 1 ('weakSet') to InspectorFrontendHost.weakSetSize must be an instance of WeakSet"_s };
>+    return size.value();
>+}
>+
>+ExceptionOr<JSC::JSValue> InspectorFrontendHost::weakSetEntries(JSC::ExecState& exec)
>+{
>+    auto entries = InspectorUtilities::weakSetEntries(exec, 0, [&] (JSC::JSValue value) {
>+        return value;
>+    });
>+    if (!entries)
>+        return Exception { TypeError, "Argument 1 ('weakSet') to InspectorFrontendHost.weakSetEntries must be an instance of WeakSet"_s };
>+    return WTFMove(entries.value());
>+}
>+
> bool InspectorFrontendHost::supportsShowCertificate() const
> {
> #if PLATFORM(COCOA)
>diff --git a/Source/WebCore/inspector/InspectorFrontendHost.h b/Source/WebCore/inspector/InspectorFrontendHost.h
>index 3017cb76c09..f992b81bdd0 100644
>--- a/Source/WebCore/inspector/InspectorFrontendHost.h
>+++ b/Source/WebCore/inspector/InspectorFrontendHost.h
>@@ -30,6 +30,8 @@
> 
> #include "ContextMenu.h"
> #include "ContextMenuProvider.h"
>+#include "ExceptionOr.h"
>+#include <JavaScriptCore/JSCInlines.h>
> #include <wtf/RefCounted.h>
> #include <wtf/Vector.h>
> #include <wtf/text/WTFString.h>
>@@ -114,6 +116,11 @@ public:
>     void inspectInspector();
>     bool isBeingInspected();
> 
>+    ExceptionOr<unsigned> weakMapSize(JSC::ExecState&);
>+    ExceptionOr<JSC::JSValue> weakMapEntries(JSC::ExecState&);
>+    ExceptionOr<unsigned> weakSetSize(JSC::ExecState&);
>+    ExceptionOr<JSC::JSValue> weakSetEntries(JSC::ExecState&);
>+
> private:
> #if ENABLE(CONTEXT_MENUS)
>     friend class FrontendMenuProvider;
>diff --git a/Source/WebCore/inspector/InspectorFrontendHost.idl b/Source/WebCore/inspector/InspectorFrontendHost.idl
>index 023a39cbc8f..0b9249c4f45 100644
>--- a/Source/WebCore/inspector/InspectorFrontendHost.idl
>+++ b/Source/WebCore/inspector/InspectorFrontendHost.idl
>@@ -85,6 +85,11 @@
>     void beep();
>     void inspectInspector();
>     boolean isBeingInspected();
>+
>+    [MayThrowException, CallWith=ExecState] unsigned long weakMapSize(/* WeakMap */);
>+    [MayThrowException, CallWith=ExecState] any weakMapEntries(/* WeakMap */);
>+    [MayThrowException, CallWith=ExecState] unsigned long weakSetSize(/* WeakSet */);
>+    [MayThrowException, CallWith=ExecState] any weakSetEntries(/* WeakSet */);
> };
> 
> dictionary ContextMenuItem {
>diff --git a/Source/WebInspectorUI/.eslintrc b/Source/WebInspectorUI/.eslintrc
>index fc6d0eaa251..52e710480e6 100644
>--- a/Source/WebInspectorUI/.eslintrc
>+++ b/Source/WebInspectorUI/.eslintrc
>@@ -74,8 +74,6 @@
>         "InspectorFrontendHost": true,
>         "InspectorProtocol": true,
>         "InspectorTest": true,
>-        "LinkedList": true,
>-        "ListMultimap": true,
>         "Multimap": true,
>         "ProtocolTest": true,
>         "ProtocolTestHarness": true,
>diff --git a/Source/WebInspectorUI/UserInterface/Base/LinkedList.js b/Source/WebInspectorUI/UserInterface/Base/LinkedList.js
>deleted file mode 100644
>index f9978af4212..00000000000
>--- a/Source/WebInspectorUI/UserInterface/Base/LinkedList.js
>+++ /dev/null
>@@ -1,112 +0,0 @@
>-/*
>- * Copyright (C) 2016 Apple Inc. All rights reserved.
>- *
>- * Redistribution and use in source and binary forms, with or without
>- * modification, are permitted provided that the following conditions
>- * are met:
>- * 1. Redistributions of source code must retain the above copyright
>- *    notice, this list of conditions and the following disclaimer.
>- * 2. Redistributions in binary form must reproduce the above copyright
>- *    notice, this list of conditions and the following disclaimer in the
>- *    documentation and/or other materials provided with the distribution.
>- *
>- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
>- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
>- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
>- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
>- * THE POSSIBILITY OF SUCH DAMAGE.
>- */
>-
>-class LinkedList
>-{
>-    constructor()
>-    {
>-        this.head = new LinkedListNode;
>-        this.head.next = this.head.prev = this.head;
>-        this.length = 0;
>-    }
>-
>-    clear()
>-    {
>-        this.head.next = this.head.prev = this.head;
>-        this.length = 0;
>-    }
>-
>-    get last()
>-    {
>-        return this.head.prev;
>-    }
>-
>-    push(item)
>-    {
>-        let newNode = new LinkedListNode(item);
>-        let last = this.last;
>-        let head = this.head;
>-
>-        last.next = newNode;
>-        newNode.next = head;
>-        head.prev = newNode;
>-        newNode.prev = last;
>-
>-        this.length++;
>-
>-        return newNode;
>-    }
>-
>-    remove(node)
>-    {
>-        if (!node)
>-            return false;
>-
>-        node.prev.next = node.next;
>-        node.next.prev = node.prev;
>-
>-        this.length--;
>-        return true;
>-    }
>-
>-    forEach(callback)
>-    {
>-        let node = this.head;
>-        for (let i = 0, length = this.length; i < length; i++) {
>-            node = node.next;
>-            let returnValue = callback(node.value, i);
>-            if (returnValue === false)
>-                return;
>-        }
>-    }
>-
>-    toArray()
>-    {
>-        let node = this.head;
>-        let i = this.length;
>-        let result = new Array(i);
>-        while (i--) {
>-            node = node.prev;
>-            result[i] = node.value;
>-        }
>-        return result;
>-    }
>-
>-    toJSON()
>-    {
>-        return this.toArray();
>-    }
>-}
>-
>-
>-class LinkedListNode
>-{
>-    constructor(value)
>-    {
>-        this.value = value;
>-        this.prev = null;
>-        this.next = null;
>-    }
>-}
>diff --git a/Source/WebInspectorUI/UserInterface/Base/ListMultimap.js b/Source/WebInspectorUI/UserInterface/Base/ListMultimap.js
>deleted file mode 100644
>index a415fb68f64..00000000000
>--- a/Source/WebInspectorUI/UserInterface/Base/ListMultimap.js
>+++ /dev/null
>@@ -1,117 +0,0 @@
>-/*
>- * Copyright (C) 2016 Apple Inc. All rights reserved.
>- *
>- * Redistribution and use in source and binary forms, with or without
>- * modification, are permitted provided that the following conditions
>- * are met:
>- * 1. Redistributions of source code must retain the above copyright
>- *    notice, this list of conditions and the following disclaimer.
>- * 2. Redistributions in binary form must reproduce the above copyright
>- *    notice, this list of conditions and the following disclaimer in the
>- *    documentation and/or other materials provided with the distribution.
>- *
>- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
>- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
>- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
>- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
>- * THE POSSIBILITY OF SUCH DAMAGE.
>- */
>-
>-class ListMultimap
>-{
>-    constructor()
>-    {
>-        this._insertionOrderedEntries = new LinkedList;
>-        this._keyMap = new Map;
>-    }
>-
>-    get size()
>-    {
>-        return this._insertionOrderedEntries.length;
>-    }
>-
>-    add(key, value)
>-    {
>-        let nodeMap = this._keyMap.get(key);
>-        if (!nodeMap) {
>-            nodeMap = new Map;
>-            this._keyMap.set(key, nodeMap);
>-        }
>-
>-        let node = nodeMap.get(value);
>-        if (!node) {
>-            node = this._insertionOrderedEntries.push([key, value]);
>-            nodeMap.set(value, node);
>-        }
>-
>-        return this;
>-    }
>-
>-    delete(key, value)
>-    {
>-        let nodeMap = this._keyMap.get(key);
>-        if (!nodeMap)
>-            return false;
>-
>-        let node = nodeMap.get(value);
>-        if (!node)
>-            return false;
>-
>-        nodeMap.delete(value);
>-        this._insertionOrderedEntries.remove(node);
>-        return true;
>-    }
>-
>-    deleteAll(key)
>-    {
>-        let nodeMap = this._keyMap.get(key);
>-        if (!nodeMap)
>-            return false;
>-
>-        let list = this._insertionOrderedEntries;
>-        let didDelete = false;
>-        nodeMap.forEach(function(node) {
>-            list.remove(node);
>-            didDelete = true;
>-        });
>-
>-        this._keyMap.delete(key);
>-        return didDelete;
>-    }
>-
>-    has(key, value)
>-    {
>-        let nodeMap = this._keyMap.get(key);
>-        if (!nodeMap)
>-            return false;
>-
>-        return nodeMap.has(value);
>-    }
>-
>-    clear()
>-    {
>-        this._keyMap = new Map;
>-        this._insertionOrderedEntries = new LinkedList;
>-    }
>-
>-    forEach(callback)
>-    {
>-        this._insertionOrderedEntries.forEach(callback);
>-    }
>-
>-    toArray()
>-    {
>-        return this._insertionOrderedEntries.toArray();
>-    }
>-
>-    toJSON()
>-    {
>-        return this.toArray();
>-    }
>-}
>diff --git a/Source/WebInspectorUI/UserInterface/Base/Main.js b/Source/WebInspectorUI/UserInterface/Base/Main.js
>index 04047f5b99c..2431e8bb909 100644
>--- a/Source/WebInspectorUI/UserInterface/Base/Main.js
>+++ b/Source/WebInspectorUI/UserInterface/Base/Main.js
>@@ -94,7 +94,7 @@ WI.loaded = function()
> 
>     // Listen for the ProvisionalLoadStarted event before registering for events so our code gets called before any managers or sidebars.
>     // This lets us save a state cookie before any managers or sidebars do any resets that would affect state (namely TimelineManager).
>-    WI.Frame.addEventListener(WI.Frame.Event.ProvisionalLoadStarted, WI._provisionalLoadStarted,);
>+    WI.Frame.addEventListener(WI.Frame.Event.ProvisionalLoadStarted, WI._provisionalLoadStarted, WI);
> 
>     // Populate any UIStrings that must be done early after localized strings have loaded.
>     WI.KeyboardShortcut.Key.Space._displayName = WI.UIString("Space");
>@@ -125,16 +125,16 @@ WI.loaded = function()
>     ];
> 
>     // Register for events.
>-    WI.debuggerManager.addEventListener(WI.DebuggerManager.Event.Paused, WI._debuggerDidPause);
>-    WI.debuggerManager.addEventListener(WI.DebuggerManager.Event.Resumed, WI._debuggerDidResume);
>-    WI.domManager.addEventListener(WI.DOMManager.Event.InspectModeStateChanged, WI._inspectModeStateChanged);
>-    WI.domManager.addEventListener(WI.DOMManager.Event.DOMNodeWasInspected, WI._domNodeWasInspected);
>-    WI.domStorageManager.addEventListener(WI.DOMStorageManager.Event.DOMStorageObjectWasInspected, WI._domStorageWasInspected);
>-    WI.databaseManager.addEventListener(WI.DatabaseManager.Event.DatabaseWasInspected, WI._databaseWasInspected);
>-    WI.networkManager.addEventListener(WI.NetworkManager.Event.MainFrameDidChange, WI._mainFrameDidChange);
>-    WI.networkManager.addEventListener(WI.NetworkManager.Event.FrameWasAdded, WI._frameWasAdded);
>+    WI.debuggerManager.addEventListener(WI.DebuggerManager.Event.Paused, WI._debuggerDidPause, WI);
>+    WI.debuggerManager.addEventListener(WI.DebuggerManager.Event.Resumed, WI._debuggerDidResume, WI);
>+    WI.domManager.addEventListener(WI.DOMManager.Event.InspectModeStateChanged, WI._inspectModeStateChanged, WI);
>+    WI.domManager.addEventListener(WI.DOMManager.Event.DOMNodeWasInspected, WI._domNodeWasInspected, WI);
>+    WI.domStorageManager.addEventListener(WI.DOMStorageManager.Event.DOMStorageObjectWasInspected, WI._domStorageWasInspected, WI);
>+    WI.databaseManager.addEventListener(WI.DatabaseManager.Event.DatabaseWasInspected, WI._databaseWasInspected, WI);
>+    WI.networkManager.addEventListener(WI.NetworkManager.Event.MainFrameDidChange, WI._mainFrameDidChange, WI);
>+    WI.networkManager.addEventListener(WI.NetworkManager.Event.FrameWasAdded, WI._frameWasAdded, WI);
> 
>-    WI.Frame.addEventListener(WI.Frame.Event.MainResourceDidChange, WI._mainResourceDidChange);
>+    WI.Frame.addEventListener(WI.Frame.Event.MainResourceDidChange, WI._mainResourceDidChange, WI);
> 
>     document.addEventListener("DOMContentLoaded", WI.contentLoaded);
> 
>@@ -302,26 +302,26 @@ WI.contentLoaded = function()
>     document.body.classList.add(WI.sharedApp.debuggableType);
>     document.body.setAttribute("dir", WI.resolvedLayoutDirection());
> 
>-    WI.settings.showJavaScriptTypeInformation.addEventListener(WI.Setting.Event.Changed, WI._showJavaScriptTypeInformationSettingChanged);
>-    WI.settings.enableControlFlowProfiler.addEventListener(WI.Setting.Event.Changed, WI._enableControlFlowProfilerSettingChanged);
>-    WI.settings.resourceCachingDisabled.addEventListener(WI.Setting.Event.Changed, WI._resourceCachingDisabledSettingChanged);
>+    WI.settings.showJavaScriptTypeInformation.addEventListener(WI.Setting.Event.Changed, WI._showJavaScriptTypeInformationSettingChanged, WI);
>+    WI.settings.enableControlFlowProfiler.addEventListener(WI.Setting.Event.Changed, WI._enableControlFlowProfilerSettingChanged, WI);
>+    WI.settings.resourceCachingDisabled.addEventListener(WI.Setting.Event.Changed, WI._resourceCachingDisabledSettingChanged, WI);
> 
>     function setTabSize() {
>         document.body.style.tabSize = WI.settings.tabSize.value;
>     }
>-    WI.settings.tabSize.addEventListener(WI.Setting.Event.Changed, setTabSize);
>+    WI.settings.tabSize.addEventListener(WI.Setting.Event.Changed, setTabSize, WI);
>     setTabSize();
> 
>     function setInvalidCharacterClassName() {
>         document.body.classList.toggle("show-invalid-characters", WI.settings.showInvalidCharacters.value);
>     }
>-    WI.settings.showInvalidCharacters.addEventListener(WI.Setting.Event.Changed, setInvalidCharacterClassName);
>+    WI.settings.showInvalidCharacters.addEventListener(WI.Setting.Event.Changed, setInvalidCharacterClassName, WI);
>     setInvalidCharacterClassName();
> 
>     function setWhitespaceCharacterClassName() {
>         document.body.classList.toggle("show-whitespace-characters", WI.settings.showWhitespaceCharacters.value);
>     }
>-    WI.settings.showWhitespaceCharacters.addEventListener(WI.Setting.Event.Changed, setWhitespaceCharacterClassName);
>+    WI.settings.showWhitespaceCharacters.addEventListener(WI.Setting.Event.Changed, setWhitespaceCharacterClassName, WI);
>     setWhitespaceCharacterClassName();
> 
>     WI.settingsTabContentView = new WI.SettingsTabContentView;
>@@ -335,7 +335,7 @@ WI.contentLoaded = function()
>         WI.tabBar = new WI.TabBar(document.getElementById("tab-bar"));
>     else {
>         WI.tabBar = new WI.LegacyTabBar(document.getElementById("tab-bar"));
>-        WI.tabBar.addEventListener(WI.TabBar.Event.OpenDefaultTab, WI._openDefaultTab);
>+        WI.tabBar.addEventListener(WI.TabBar.Event.OpenDefaultTab, WI._openDefaultTab, WI);
>     }
> 
>     WI._contentElement = document.getElementById("content");
>@@ -351,8 +351,8 @@ WI.contentLoaded = function()
>     WI.findPreviousKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.Shift | WI.KeyboardShortcut.Modifier.CommandOrControl, "G", WI._findPrevious);
> 
>     WI.consoleDrawer = new WI.ConsoleDrawer(document.getElementById("console-drawer"));
>-    WI.consoleDrawer.addEventListener(WI.ConsoleDrawer.Event.CollapsedStateChanged, WI._consoleDrawerCollapsedStateDidChange);
>-    WI.consoleDrawer.addEventListener(WI.ConsoleDrawer.Event.Resized, WI._consoleDrawerDidResize);
>+    WI.consoleDrawer.addEventListener(WI.ConsoleDrawer.Event.CollapsedStateChanged, WI._consoleDrawerCollapsedStateDidChange, WI);
>+    WI.consoleDrawer.addEventListener(WI.ConsoleDrawer.Event.Resized, WI._consoleDrawerDidResize, WI);
> 
>     WI.quickConsole = new WI.QuickConsole(document.getElementById("quick-console"));
> 
>@@ -363,10 +363,10 @@ WI.contentLoaded = function()
> 
>     // FIXME: The sidebars should be flipped in RTL languages.
>     WI.navigationSidebar = new WI.Sidebar(document.getElementById("navigation-sidebar"), WI.Sidebar.Sides.Left);
>-    WI.navigationSidebar.addEventListener(WI.Sidebar.Event.WidthDidChange, WI._sidebarWidthDidChange);
>+    WI.navigationSidebar.addEventListener(WI.Sidebar.Event.WidthDidChange, WI._sidebarWidthDidChange, WI);
> 
>     WI.detailsSidebar = new WI.Sidebar(document.getElementById("details-sidebar"), WI.Sidebar.Sides.Right, null, null, WI.UIString("Details"), true);
>-    WI.detailsSidebar.addEventListener(WI.Sidebar.Event.WidthDidChange, WI._sidebarWidthDidChange);
>+    WI.detailsSidebar.addEventListener(WI.Sidebar.Event.WidthDidChange, WI._sidebarWidthDidChange, WI);
> 
>     WI.searchKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl | WI.KeyboardShortcut.Modifier.Shift, "F", WI._focusSearchField);
>     WI._findKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl, "F", WI._find);
>@@ -391,7 +391,7 @@ WI.contentLoaded = function()
>     WI._openNewTabKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl | WI.KeyboardShortcut.Modifier.Option, "T", WI.showNewTabTab);
> 
>     WI.tabBrowser = new WI.TabBrowser(document.getElementById("tab-browser"), WI.tabBar, WI.navigationSidebar, WI.detailsSidebar);
>-    WI.tabBrowser.addEventListener(WI.TabBrowser.Event.SelectedTabContentViewDidChange, WI._tabBrowserSelectedTabContentViewDidChange);
>+    WI.tabBrowser.addEventListener(WI.TabBrowser.Event.SelectedTabContentViewDidChange, WI._tabBrowserSelectedTabContentViewDidChange, WI);
> 
>     WI._reloadPageKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl, "R", WI._reloadPage);
>     WI._reloadPageFromOriginKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl | WI.KeyboardShortcut.Modifier.Option, "R", WI._reloadPageFromOrigin);
>@@ -418,22 +418,22 @@ WI.contentLoaded = function()
>     WI.stepOutAlternateKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.Shift | WI.KeyboardShortcut.Modifier.CommandOrControl, WI.KeyboardShortcut.Key.Semicolon, WI.debuggerStepOut);
> 
>     WI._closeToolbarButton = new WI.ControlToolbarItem("dock-close", WI.UIString("Close"), "Images/Close.svg", 16, 14);
>-    WI._closeToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI.close);
>+    WI._closeToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI.close, WI);
> 
>     WI._undockToolbarButton = new WI.ButtonToolbarItem("undock", WI.UIString("Detach into separate window"), "Images/Undock.svg");
>     WI._undockToolbarButton.element.classList.add(WI.Popover.IgnoreAutoDismissClassName);
>-    WI._undockToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._undock);
>+    WI._undockToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._undock, WI);
> 
>     let dockImage = WI.resolvedLayoutDirection() === WI.LayoutDirection.RTL ? "Images/DockLeft.svg" : "Images/DockRight.svg";
>     WI._dockToSideToolbarButton = new WI.ButtonToolbarItem("dock-right", WI.UIString("Dock to side of window"), dockImage);
>     WI._dockToSideToolbarButton.element.classList.add(WI.Popover.IgnoreAutoDismissClassName);
> 
>     let dockToSideCallback = WI.resolvedLayoutDirection() === WI.LayoutDirection.RTL ? WI._dockLeft : WI._dockRight;
>-    WI._dockToSideToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, dockToSideCallback);
>+    WI._dockToSideToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, dockToSideCallback, WI);
> 
>     WI._dockBottomToolbarButton = new WI.ButtonToolbarItem("dock-bottom", WI.UIString("Dock to bottom of window"), "Images/DockBottom.svg");
>     WI._dockBottomToolbarButton.element.classList.add(WI.Popover.IgnoreAutoDismissClassName);
>-    WI._dockBottomToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._dockBottom);
>+    WI._dockBottomToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._dockBottom, WI);
> 
>     WI._togglePreviousDockConfigurationKeyboardShortcut = new WI.KeyboardShortcut(WI.KeyboardShortcut.Modifier.CommandOrControl | WI.KeyboardShortcut.Modifier.Shift, "D", WI._togglePreviousDockConfiguration);
> 
>@@ -443,21 +443,21 @@ WI.contentLoaded = function()
>     else
>         reloadToolTip = WI.UIString("Reload page (%s)\nReload page ignoring cache (%s)").format(WI._reloadPageKeyboardShortcut.displayName, WI._reloadPageFromOriginKeyboardShortcut.displayName);
>     WI._reloadToolbarButton = new WI.ButtonToolbarItem("reload", reloadToolTip, "Images/ReloadToolbar.svg");
>-    WI._reloadToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._reloadToolbarButtonClicked);
>+    WI._reloadToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._reloadToolbarButtonClicked, WI);
> 
>     WI._downloadToolbarButton = new WI.ButtonToolbarItem("download", WI.UIString("Download Web Archive"), "Images/DownloadArrow.svg");
>-    WI._downloadToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._downloadWebArchive);
>+    WI._downloadToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._downloadWebArchive, WI);
> 
>     let elementSelectionToolTip = WI.UIString("Start element selection (%s)").format(WI._inspectModeKeyboardShortcut.displayName);
>     let activatedElementSelectionToolTip = WI.UIString("Stop element selection (%s)").format(WI._inspectModeKeyboardShortcut.displayName);
>     WI._inspectModeToolbarButton = new WI.ActivateButtonToolbarItem("inspect", elementSelectionToolTip, activatedElementSelectionToolTip, "Images/Crosshair.svg");
>-    WI._inspectModeToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._toggleInspectMode);
>+    WI._inspectModeToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._toggleInspectMode, WI);
> 
>     // COMPATIBILITY (iOS 12.2): Page.overrideSetting did not exist.
>     if (InspectorFrontendHost.isRemote && WI.sharedApp.debuggableType === WI.DebuggableType.Web && InspectorBackend.domains.Page && InspectorBackend.domains.Page.overrideUserAgent && InspectorBackend.domains.Page.overrideSetting) {
>         const deviceSettingsTooltip = WI.UIString("Device Settings");
>         WI._deviceSettingsToolbarButton = new WI.ActivateButtonToolbarItem("device-settings", deviceSettingsTooltip, deviceSettingsTooltip, "Images/Device.svg");
>-        WI._deviceSettingsToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._handleDeviceSettingsToolbarButtonClicked);
>+        WI._deviceSettingsToolbarButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, WI._handleDeviceSettingsToolbarButtonClicked, WI);
> 
>         WI._deviceSettingsPopover = null;
>     }
>@@ -498,7 +498,7 @@ WI.contentLoaded = function()
>     } else {
>         const incremental = false;
>         WI._searchToolbarItem = new WI.SearchBar("inspector-search", WI.UIString("Search"), incremental);
>-        WI._searchToolbarItem.addEventListener(WI.SearchBar.Event.TextChanged, WI._searchTextDidChange);
>+        WI._searchToolbarItem.addEventListener(WI.SearchBar.Event.TextChanged, WI._searchTextDidChange, WI);
>         WI.toolbar.addToolbarItem(WI._searchToolbarItem, WI.Toolbar.Section.Right);
>     }
> 
>@@ -574,9 +574,9 @@ WI.contentLoaded = function()
>         WI.showNewTabTab({suppressAnimations: true});
> 
>     // Listen to the events after restoring the saved tabs to avoid recursion.
>-    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemAdded, WI._rememberOpenTabs);
>-    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemRemoved, WI._rememberOpenTabs);
>-    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemsReordered, WI._rememberOpenTabs);
>+    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemAdded, WI._rememberOpenTabs, WI);
>+    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemRemoved, WI._rememberOpenTabs, WI);
>+    WI.tabBar.addEventListener(WI.TabBar.Event.TabBarItemsReordered, WI._rememberOpenTabs, WI);
> 
>     // Signal that the frontend is now ready to receive messages.
>     WI.whenTargetsAvailable().then(() => {
>diff --git a/Source/WebInspectorUI/UserInterface/Base/Object.js b/Source/WebInspectorUI/UserInterface/Base/Object.js
>index 4802881f7c7..0b36cc02be2 100644
>--- a/Source/WebInspectorUI/UserInterface/Base/Object.js
>+++ b/Source/WebInspectorUI/UserInterface/Base/Object.js
>@@ -34,95 +34,123 @@ WI.Object = class WebInspectorObject
> 
>     static addEventListener(eventType, listener, thisObject)
>     {
>-        thisObject = thisObject || null;
>-
>-        console.assert(eventType, "Object.addEventListener: invalid event type ", eventType, "(listener: ", listener, "thisObject: ", thisObject, ")");
>+        console.assert(eventType, "Object.addEventListener: invalid eventType ", eventType, "(listener: ", listener, " thisObject: ", thisObject, ")");
>         if (!eventType)
>             return null;
> 
>-        console.assert(listener, "Object.addEventListener: invalid listener ", listener, "(event type: ", eventType, "thisObject: ", thisObject, ")");
>+        console.assert(listener, "Object.addEventListener: invalid listener ", listener, "(eventType: ", eventType, " thisObject: ", thisObject, ")");
>         if (!listener)
>             return null;
> 
>-        if (!this._listeners)
>-            this._listeners = new Map();
>+        if (window.InspectorTest && !thisObject)
>+            thisObject = this;
> 
>-        let listenersTable = this._listeners.get(eventType);
>-        if (!listenersTable) {
>-            listenersTable = new ListMultimap();
>-            this._listeners.set(eventType, listenersTable);
>+        console.assert(thisObject && thisObject instanceof Object, "Object.addEventListener: invalid thisObject ", thisObject, "(eventType: ", eventType, " listener:", listener, ")");
>+        if (!thisObject || !(thisObject instanceof Object))
>+            return null;
>+
>+        if (!this._listeners)
>+            this._listeners = new Map;
>+
>+        let thisObjectsForEventType = this._listeners.get(eventType);
>+        if (!thisObjectsForEventType) {
>+            thisObjectsForEventType = new WeakMap;
>+            this._listeners.set(eventType, thisObjectsForEventType);
>         }
> 
>-        listenersTable.add(thisObject, listener);
>+        let listenersForThisObject = thisObjectsForEventType.get(thisObject);
>+        if (!listenersForThisObject) {
>+            listenersForThisObject = new Set;
>+            thisObjectsForEventType.set(thisObject, listenersForThisObject);
>+        }
>+
>+        console.assert(!listenersForThisObject.has(listener), "Object.addEventListener: duplicate listener ", listener, "(eventType: ", eventType, " thisObject ", thisObject, ")");
>+        listenersForThisObject.add(listener);
>+
>         return listener;
>     }
> 
>     static singleFireEventListener(eventType, listener, thisObject)
>     {
>-        let wrappedCallback = function() {
>-            this.removeEventListener(eventType, wrappedCallback, null);
>-            listener.apply(thisObject, arguments);
>-        }.bind(this);
>-
>-        this.addEventListener(eventType, wrappedCallback, null);
>+        let wrappedCallback = (...args) => {
>+            this.removeEventListener(eventType, wrappedCallback, thisObject);
>+            listener.apply(thisObject, ...args);
>+        };
>+        this.addEventListener(eventType, wrappedCallback, thisObject);
>         return wrappedCallback;
>     }
> 
>     static removeEventListener(eventType, listener, thisObject)
>     {
>-        eventType = eventType || null;
>-        listener = listener || null;
>-        thisObject = thisObject || null;
>-
>+        console.assert(this._listeners);
>         if (!this._listeners)
>             return;
> 
>-        if (thisObject && !eventType) {
>-            this._listeners.forEach(function(listenersTable) {
>-                listenersTable.deleteAll(thisObject);
>+        if (!eventType && !listener && thisObject) {
>+            this._listeners.forEach((thisObjectsForEventType) => {
>+                thisObjectsForEventType.delete(thisObject);
>             });
>-
>             return;
>         }
> 
>-        let listenersTable = this._listeners.get(eventType);
>-        if (!listenersTable || listenersTable.size === 0)
>+        let thisObjectsForEventType = this._listeners.get(eventType);
>+        console.assert(thisObjectsForEventType, "Object.removeEventListener: unknown eventType ", eventType, "(listener: ", listener, "thisObject: ", thisObject, ")");
>+        if (!thisObjectsForEventType)
>             return;
> 
>-        let didDelete = listenersTable.delete(thisObject, listener);
>-        console.assert(didDelete, "removeEventListener cannot remove " + eventType.toString() + " because it doesn't exist.");
>+        let listenersForThisObject = thisObjectsForEventType.get(thisObject);
>+        console.assert(listenersForThisObject, "Object.removeEventListener: unknown thisObject ", thisObject, "(eventType: ", eventType, "listener: ", listener, ")");
>+        if (!listenersForThisObject)
>+            return;
>+
>+        let didDelete = listenersForThisObject.delete(listener);
>+        console.assert(didDelete, "Object.removeEventListener: missing listener ", listener, "(eventType: ", eventType, " thisObject ", thisObject, ")");
>+
>+        if (!listenersForThisObject.size) {
>+            thisObjectsForEventType.delete(thisObject);
>+
>+            if (!InspectorFrontendHost.weakMapSize(thisObjectsForEventType)) {
>+                this._listeners.delete(eventType);
>+
>+                if (!this._listeners.size)
>+                    this._listeners = null;
>+            }
>+        }
>     }
> 
>-    static awaitEvent(eventType)
>+    static async awaitEvent(eventType, thisObject)
>     {
>-        let wrapper = new WI.WrappedPromise;
>-        this.singleFireEventListener(eventType, (event) => wrapper.resolve(event));
>-        return wrapper.promise;
>+        return new Promise((resolve, reject) => {
>+            this.singleFireEventListener(eventType, resolve, thisObject || this);
>+        });
>     }
> 
>     // Only used by tests.
>     static hasEventListeners(eventType)
>     {
>+        console.assert(window.InspectorTest);
>+
>         if (!this._listeners)
>             return false;
> 
>-        let listenersTable = this._listeners.get(eventType);
>-        return listenersTable && listenersTable.size > 0;
>+        let thisObjectsForEventType = this._listeners.get(eventType);
>+        return thisObjectsForEventType && InspectorFrontendHost.weakMapSize(thisObjectsForEventType) > 0;
>     }
> 
>     // This should only be used within regression tests to detect leaks.
>-    static retainedObjectsWithPrototype(proto)
>+    static activelyListeningObjectsWithPrototype(proto)
>     {
>+        console.assert(window.InspectorTest);
>+
>         let results = new Set;
> 
>         if (this._listeners) {
>-            this._listeners.forEach(function(listenersTable, eventType) {
>-                listenersTable.forEach(function(pair) {
>-                    let thisObject = pair[0];
>-                    if (thisObject instanceof proto)
>+            for (let thisObjectsForEventType of this._listeners.values()) {
>+                for (let [thisObject, listenersForThisObject] of InspectorFrontendHost.weakMapEntries(thisObjectsForEventType)) {
>+                    if (thisObject instanceof proto && listenersForThisObject.size > 0)
>                         results.add(thisObject);
>-                });
>-            });
>+                }
>+            }
>         }
> 
>         return results;
>@@ -135,7 +163,7 @@ WI.Object = class WebInspectorObject
>     removeEventListener() { return WI.Object.removeEventListener.apply(this, arguments); }
>     awaitEvent() { return WI.Object.awaitEvent.apply(this, arguments); }
>     hasEventListeners() { return WI.Object.hasEventListeners.apply(this, arguments); }
>-    retainedObjectsWithPrototype() { return WI.Object.retainedObjectsWithPrototype.apply(this, arguments); }
>+    activelyListeningObjectsWithPrototype() { return WI.Object.activelyListeningObjectsWithPrototype.apply(this, arguments); }
> 
>     dispatchEventToListeners(eventType, eventData)
>     {
>@@ -146,25 +174,20 @@ WI.Object = class WebInspectorObject
>             if (!object || event._stoppedPropagation)
>                 return;
> 
>-            let listenerTypesMap = object._listeners;
>-            if (!listenerTypesMap || !object.hasOwnProperty("_listeners"))
>+            let listeners = object._listeners;
>+            if (!listeners || !object.hasOwnProperty("_listeners"))
>                 return;
> 
>-            console.assert(listenerTypesMap instanceof Map);
>-
>-            let listenersTable = listenerTypesMap.get(eventType);
>-            if (!listenersTable)
>+            let thisObjectsForEventType = listeners.get(eventType);
>+            if (!thisObjectsForEventType)
>                 return;
> 
>-            // Make a copy with slice so mutations during the loop doesn't affect us.
>-            let listeners = listenersTable.toArray();
>-
>-            // Iterate over the listeners and call them. Stop if stopPropagation is called.
>-            for (let i = 0, length = listeners.length; i < length; ++i) {
>-                let [thisObject, listener] = listeners[i];
>-                listener.call(thisObject, event);
>-                if (event._stoppedPropagation)
>-                    break;
>+            for (let [thisObject, listenersForThisObject] of InspectorFrontendHost.weakMapEntries(thisObjectsForEventType)) {
>+                for (let listener of listenersForThisObject) {
>+                    listener.call(thisObject, event);
>+                    if (event._stoppedPropagation)
>+                        return;
>+                }
>             }
>         }
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Base/SearchUtilities.js b/Source/WebInspectorUI/UserInterface/Base/SearchUtilities.js
>index 5a58656861a..a41c5561eda 100644
>--- a/Source/WebInspectorUI/UserInterface/Base/SearchUtilities.js
>+++ b/Source/WebInspectorUI/UserInterface/Base/SearchUtilities.js
>@@ -32,18 +32,15 @@ WI.SearchUtilities = class SearchUtilities {
>         };
>     }
> 
>-    static createSettings(namePrefix, options = {})
>+    static createSettings(namePrefix)
>     {
>         let settings = {};
>         for (let [key, defaultSetting] of Object.entries(WI.SearchUtilities.defaultSettings)) {
>             let setting = new WI.Setting(namePrefix + "-" + defaultSetting.name, defaultSetting.value);
>-            defaultSetting.addEventListener(WI.Setting.Event.Changed, (event) => {
>+            defaultSetting.addEventListener(WI.Setting.Event.Changed, function(event) {
>                 setting.value = defaultSetting.value;
>-            });
>+            }, setting);
>             settings[key] = setting;
>-
>-            if (options.handleChanged)
>-                setting.addEventListener(WI.Setting.Event.Changed, options.handleChanged);
>         }
>         return settings;
>     }
>@@ -110,8 +107,8 @@ WI.SearchUtilities = class SearchUtilities {
>         function toggleActive() {
>             button.classList.toggle("active", Object.values(settings).some((setting) => !!setting.value));
>         }
>-        settings.caseSensitive.addEventListener(WI.Setting.Event.Changed, toggleActive);
>-        settings.regularExpression.addEventListener(WI.Setting.Event.Changed, toggleActive);
>+        settings.caseSensitive.addEventListener(WI.Setting.Event.Changed, toggleActive, button);
>+        settings.regularExpression.addEventListener(WI.Setting.Event.Changed, toggleActive, button);
>         toggleActive();
> 
>         return button;
>diff --git a/Source/WebInspectorUI/UserInterface/Controllers/CodeMirrorColorEditingController.js b/Source/WebInspectorUI/UserInterface/Controllers/CodeMirrorColorEditingController.js
>index 3c9995c2cd7..ef9e6ab61ef 100644
>--- a/Source/WebInspectorUI/UserInterface/Controllers/CodeMirrorColorEditingController.js
>+++ b/Source/WebInspectorUI/UserInterface/Controllers/CodeMirrorColorEditingController.js
>@@ -41,7 +41,9 @@ WI.CodeMirrorColorEditingController = class CodeMirrorColorEditingController ext
>     {
>         this._colorPicker = new WI.ColorPicker;
>         this._colorPicker.addEventListener(WI.ColorPicker.Event.ColorChanged, this._colorPickerColorChanged, this);
>-        this._colorPicker.addEventListener(WI.ColorPicker.Event.FormatChanged, (event) => popover.update());
>+        this._colorPicker.addEventListener(WI.ColorPicker.Event.FormatChanged, function(event) {
>+            popover.update();
>+        }, this);
>         popover.content = this._colorPicker.element;
>     }
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Debug/Bootstrap.js b/Source/WebInspectorUI/UserInterface/Debug/Bootstrap.js
>index 0ec34df34b7..825f7db1567 100644
>--- a/Source/WebInspectorUI/UserInterface/Debug/Bootstrap.js
>+++ b/Source/WebInspectorUI/UserInterface/Debug/Bootstrap.js
>@@ -80,7 +80,7 @@ WI.runBootstrapOperations = function() {
>     }
> 
>     WI.toolbar.addToolbarItem(dumpMessagesToolbarItem, WI.Toolbar.Section.CenterRight);
>-    dumpMessagesToolbarItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+    dumpMessagesToolbarItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>         let nextState;
>         switch (dumpMessagesCurrentState()) {
>         case DumpMessagesState.Off:
>@@ -94,12 +94,12 @@ WI.runBootstrapOperations = function() {
>             break;
>         }
>         applyDumpMessagesState(nextState);
>-    });
>-    WI.settings.autoLogProtocolMessages.addEventListener(WI.Setting.Event.Changed, () => {
>+    }, WI);
>+    WI.settings.autoLogProtocolMessages.addEventListener(WI.Setting.Event.Changed, function(event) {
>         if (ignoreChangesToState)
>             return;
>         applyDumpMessagesState(dumpMessagesCurrentState());
>-    });
>+    }, WI);
>     applyDumpMessagesState(dumpMessagesCurrentState());
> 
>     // Next Level Inspector.
>@@ -108,19 +108,19 @@ WI.runBootstrapOperations = function() {
>     let inspectInspectorToolbarItem = new WI.ButtonToolbarItem("inspect-inspector", inspectInspectorToolTip);
>     WI.toolbar.addToolbarItem(inspectInspectorToolbarItem, WI.Toolbar.Section.CenterRight);
>     inspectInspectorToolbarItem.element.textContent = inspectionLevel + 1;
>-    inspectInspectorToolbarItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+    inspectInspectorToolbarItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>         InspectorFrontendHost.inspectInspector();
>-    });
>+    }, WI);
> 
>     function updateDebugUI() {
>         dumpMessagesToolbarItem.hidden = !WI.showDebugUISetting.value;
>         inspectInspectorToolbarItem.hidden = !WI.showDebugUISetting.value;
>     }
> 
>-    WI.showDebugUISetting.addEventListener(WI.Setting.Event.Changed, () => {
>+    WI.showDebugUISetting.addEventListener(WI.Setting.Event.Changed, function(event) {
>         updateDebugUI();
>         WI.notifications.dispatchEventToListeners(WI.Notification.DebugUIEnabledDidChange);
>-    });
>+    }, WI);
> 
>     updateDebugUI();
> };
>diff --git a/Source/WebInspectorUI/UserInterface/Main.html b/Source/WebInspectorUI/UserInterface/Main.html
>index 6b4d613704f..e9e94ede089 100644
>--- a/Source/WebInspectorUI/UserInterface/Main.html
>+++ b/Source/WebInspectorUI/UserInterface/Main.html
>@@ -279,8 +279,6 @@
>     <script src="Base/Platform.js"></script>
>     <script src="Base/Debouncer.js"></script>
>     <script src="Base/DebuggableType.js"></script>
>-    <script src="Base/LinkedList.js"></script>
>-    <script src="Base/ListMultimap.js"></script>
>     <script src="Base/Multimap.js"></script>
>     <script src="Base/Object.js"></script>
>     <script src="Base/Throttler.js"></script>
>diff --git a/Source/WebInspectorUI/UserInterface/Models/Resource.js b/Source/WebInspectorUI/UserInterface/Models/Resource.js
>index e931c127481..e4ffa001bfe 100644
>--- a/Source/WebInspectorUI/UserInterface/Models/Resource.js
>+++ b/Source/WebInspectorUI/UserInterface/Models/Resource.js
>@@ -1002,8 +1002,8 @@ WI.Resource = class Resource extends WI.SourceCode
> 
>         if (!this._finishThenRequestContentPromise) {
>             this._finishThenRequestContentPromise = new Promise((resolve, reject) => {
>-                this.addEventListener(WI.Resource.Event.LoadingDidFinish, resolve);
>-                this.addEventListener(WI.Resource.Event.LoadingDidFail, reject);
>+                this.addEventListener(WI.Resource.Event.LoadingDidFinish, resolve, this);
>+                this.addEventListener(WI.Resource.Event.LoadingDidFail, reject, this);
>             }).then(WI.SourceCode.prototype.requestContent.bind(this));
>         }
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Test.html b/Source/WebInspectorUI/UserInterface/Test.html
>index e710ec6573d..5f123b3155c 100644
>--- a/Source/WebInspectorUI/UserInterface/Test.html
>+++ b/Source/WebInspectorUI/UserInterface/Test.html
>@@ -39,8 +39,6 @@
>     <script src="Base/Platform.js"></script>
>     <script src="Base/Debouncer.js"></script>
>     <script src="Base/DebuggableType.js"></script>
>-    <script src="Base/LinkedList.js"></script>
>-    <script src="Base/ListMultimap.js"></script>
>     <script src="Base/Multimap.js"></script>
>     <script src="Base/Object.js"></script>
>     <script src="Base/Throttler.js"></script>
>diff --git a/Source/WebInspectorUI/UserInterface/TestStub.html b/Source/WebInspectorUI/UserInterface/TestStub.html
>index 3f522e9f64c..294a53fb55d 100644
>--- a/Source/WebInspectorUI/UserInterface/TestStub.html
>+++ b/Source/WebInspectorUI/UserInterface/TestStub.html
>@@ -30,8 +30,6 @@ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>     These resources should match the order and groups used in Main.html and Test.html.
>     -->
>     <script src="Base/WebInspector.js"></script>
>-    <script src="Base/LinkedList.js"></script>
>-    <script src="Base/ListMultimap.js"></script>
>     <script src="Base/Object.js"></script>
>     <script src="Base/Utilities.js"></script>
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Views/AuditNavigationSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/AuditNavigationSidebarPanel.js
>index b5c196dae16..761fff057d1 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/AuditNavigationSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/AuditNavigationSidebarPanel.js
>@@ -42,9 +42,9 @@ WI.AuditNavigationSidebarPanel = class AuditNavigationSidebarPanel extends WI.Na
>             contentView.element.appendChild(contentPlaceholder);
> 
>             let finishEditingNavigationItem = new WI.ButtonNavigationItem("finish-editing-audits", WI.UIString("Done"));
>-            finishEditingNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, (event) => {
>+            finishEditingNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>                 WI.auditManager.editing = false;
>-            });
>+            }, WI);
> 
>             let importHelpElement = WI.createNavigationItemHelp(WI.UIString("Press %s to stop editing"), finishEditingNavigationItem);
>             contentPlaceholder.appendChild(importHelpElement);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/AuditTestContentView.js b/Source/WebInspectorUI/UserInterface/Views/AuditTestContentView.js
>index 0597e10c295..262d2cba250 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/AuditTestContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/AuditTestContentView.js
>@@ -165,9 +165,9 @@ WI.AuditTestContentView = class AuditTestContentView extends WI.ContentView
> 
>             let startNavigationItem = new WI.ButtonNavigationItem("run-audit", WI.UIString("Start"), "Images/AuditStart.svg", 15, 15);
>             startNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
>-            startNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+            startNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>                 WI.auditManager.start([this.representedObject]);
>-            });
>+            }, this);
> 
>             let importHelpElement = WI.createNavigationItemHelp(WI.UIString("Press %s to start running the audit"), startNavigationItem);
>             this.placeholderElement.appendChild(importHelpElement);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ChangesDetailsSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/ChangesDetailsSidebarPanel.js
>index 9f96618875f..ceb4beab7b2 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ChangesDetailsSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ChangesDetailsSidebarPanel.js
>@@ -68,9 +68,10 @@ WI.ChangesDetailsSidebarPanel = class ChangesDetailsSidebarPanel extends WI.DOMD
> 
>     detached()
>     {
>-        super.detached();
>+        if (this.didInitialLayout)
>+            WI.Frame.removeEventListener(WI.Frame.Event.MainResourceDidChange, this._mainResourceDidChange, this);
> 
>-        WI.Frame.removeEventListener(WI.Frame.Event.MainResourceDidChange, this._mainResourceDidChange, this);
>+        super.detached();
>     }
> 
>     // Protected
>diff --git a/Source/WebInspectorUI/UserInterface/Views/CodeMirrorEditor.js b/Source/WebInspectorUI/UserInterface/Views/CodeMirrorEditor.js
>index e445dd3156b..1c613d20208 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/CodeMirrorEditor.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/CodeMirrorEditor.js
>@@ -47,9 +47,9 @@ WI.CodeMirrorEditor = class CodeMirrorEditor
>             if (options[codeMirrorOption] !== undefined)
>                 return;
> 
>-            setting.addEventListener(WI.Setting.Event.Changed, (event) => {
>+            setting.addEventListener(WI.Setting.Event.Changed, function(event) {
>                 codeMirror.setOption(codeMirrorOption, setting.value);
>-            });
>+            }, codeMirror);
>         }
>         listenForChange(WI.settings.indentWithTabs, "indentWithTabs");
>         listenForChange(WI.settings.indentUnit, "indentUnit");
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ConsoleDrawer.js b/Source/WebInspectorUI/UserInterface/Views/ConsoleDrawer.js
>index 16929cd2276..b49aef5e75c 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ConsoleDrawer.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ConsoleDrawer.js
>@@ -41,7 +41,9 @@ WI.ConsoleDrawer = class ConsoleDrawer extends WI.ContentBrowser
>         this._toggleDrawerButton = new WI.ToggleButtonNavigationItem("toggle-drawer", WI.UIString("Hide Console"), WI.UIString("Show Console"), "Images/HideConsoleDrawer.svg", "Images/ShowConsoleDrawer.svg");
> 
>         this._toggleDrawerButton.visibilityPriority = WI.NavigationItem.VisibilityPriority.High;
>-        this._toggleDrawerButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => { WI.toggleSplitConsole(); });
>+        this._toggleDrawerButton.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>+            WI.toggleSplitConsole();
>+        }, WI);
>         this.navigationBar.insertNavigationItem(this._toggleDrawerButton, 0);
> 
>         this.collapsed = true;
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ContentBrowser.js b/Source/WebInspectorUI/UserInterface/Views/ContentBrowser.js
>index 7e9a2f91eff..77338caf5b2 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ContentBrowser.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ContentBrowser.js
>@@ -55,11 +55,11 @@ WI.ContentBrowser = class ContentBrowser extends WI.View
>             let forwardButtonImage = isRTL ? leftArrow : rightArrow;
> 
>             this._backNavigationItem = new WI.ButtonNavigationItem("back", WI.UIString("Back (%s)").format(this._backKeyboardShortcut.displayName), backButtonImage, 8, 13);
>-            this._backNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, goBack);
>+            this._backNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, goBack, this);
>             this._backNavigationItem.enabled = false;
> 
>             this._forwardNavigationItem = new WI.ButtonNavigationItem("forward", WI.UIString("Forward (%s)").format(this._forwardKeyboardShortcut.displayName), forwardButtonImage, 8, 13);
>-            this._forwardNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, goForward);
>+            this._forwardNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, goForward, this);
>             this._forwardNavigationItem.enabled = false;
> 
>             let navigationButtonsGroup = new WI.GroupNavigationItem([this._backNavigationItem, this._forwardNavigationItem]);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/DataGridNode.js b/Source/WebInspectorUI/UserInterface/Views/DataGridNode.js
>index d90a9480ae0..32f48d28292 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/DataGridNode.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/DataGridNode.js
>@@ -442,8 +442,6 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>         for (var i = 0; i < this.children.length; ++i)
>             this.children[i].revealed = false;
> 
>-        this.dispatchEventToListeners("collapsed");
>-
>         if (this.dataGrid) {
>             this.dataGrid.dispatchEventToListeners(WI.DataGrid.Event.CollapsedNode, {dataGridNode: this});
>             this.dataGrid._noteRowsChanged();
>@@ -473,7 +471,7 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>             for (var i = 0; i < this.children.length; ++i)
>                 this.children[i]._detach();
> 
>-            this.dispatchEventToListeners("populate");
>+            this.dispatchEventToListeners(DataGridNode.Event.Populate);
> 
>             if (this._attached) {
>                 for (var i = 0; i < this.children.length; ++i) {
>@@ -492,8 +490,6 @@ WI.DataGridNode = class DataGridNode extends WI.Object
> 
>         this._expanded = true;
> 
>-        this.dispatchEventToListeners("expanded");
>-
>         if (this.dataGrid) {
>             this.dataGrid.dispatchEventToListeners(WI.DataGrid.Event.ExpandedNode, {dataGridNode: this});
>             this.dataGrid._noteRowsChanged();
>@@ -545,8 +541,6 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>         }
> 
>         this.dataGrid.updateVisibleRows(this);
>-
>-        this.dispatchEventToListeners("revealed");
>     }
> 
>     select(suppressSelectedEvent)
>@@ -592,7 +586,7 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>     traverseNextNode(skipHidden, stayWithin, dontPopulate, info)
>     {
>         if (!dontPopulate && this.hasChildren)
>-            this.dispatchEventToListeners("populate");
>+            this.dispatchEventToListeners(DataGridNode.Event.Populate);
> 
>         if (info)
>             info.depthChange = 0;
>@@ -628,11 +622,11 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>     {
>         var node = (!skipHidden || this.revealed) ? this.previousSibling : null;
>         if (!dontPopulate && node && node.hasChildren)
>-            node.dispatchEventToListeners("populate");
>+            node.dispatchEventToListeners(DataGridNode.Event.Populate);
> 
>         while (node && ((!skipHidden || (node.revealed && node.expanded)) ? node.children.lastValue : null)) {
>             if (!dontPopulate && node.hasChildren)
>-                node.dispatchEventToListeners("populate");
>+                node.dispatchEventToListeners(DataGridNode.Event.Populate);
>             node = (!skipHidden || (node.revealed && node.expanded)) ? node.children.lastValue : null;
>         }
> 
>@@ -754,6 +748,10 @@ WI.DataGridNode = class DataGridNode extends WI.Object
>     }
> };
> 
>+WI.DataGridNode.Event = {
>+    Populate: "data-grid-node-populate",
>+};
>+
> // Used to create a new table row when entering new data by editing cells.
> WI.PlaceholderDataGridNode = class PlaceholderDataGridNode extends WI.DataGridNode
> {
>diff --git a/Source/WebInspectorUI/UserInterface/Views/DebuggerSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/DebuggerSidebarPanel.js
>index 9bb6a68485e..57fe1d8db7b 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/DebuggerSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/DebuggerSidebarPanel.js
>@@ -331,9 +331,9 @@ WI.DebuggerSidebarPanel = class DebuggerSidebarPanel extends WI.NavigationSideba
> 
>     createContentTreeOutline(options = {})
>     {
>-        let treeOutline = super.createContentTreeOutline(options)
>+        let treeOutline = super.createContentTreeOutline(options);
> 
>-        treeOutline.addEventListener(WI.TreeOutline.Event.ElementRevealed, (event) => {
>+        treeOutline.addEventListener(WI.TreeOutline.Event.ElementRevealed, function(event) {
>             let treeElement = event.data.element;
>             let detailsSections = [this._pauseReasonSection, this._callStackSection, this._breakpointsSection, this._scriptsSection];
>             let detailsSection = detailsSections.find((detailsSection) => detailsSection.element.contains(treeElement.listItemElement));
>@@ -347,7 +347,7 @@ WI.DebuggerSidebarPanel = class DebuggerSidebarPanel extends WI.NavigationSideba
>             let offset = detailsSection.headerElement.totalOffsetBottom - treeElement.listItemElement.totalOffsetTop;
>             if (offset > 0)
>                 this.scrollElement.scrollBy(0, -offset);
>-        });
>+        }, this);
> 
>         return treeOutline;
>     }
>diff --git a/Source/WebInspectorUI/UserInterface/Views/DefaultDashboardView.js b/Source/WebInspectorUI/UserInterface/Views/DefaultDashboardView.js
>index 7faf0d5a6c6..eb0f2218cac 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/DefaultDashboardView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/DefaultDashboardView.js
>@@ -29,7 +29,10 @@ WI.DefaultDashboardView = class DefaultDashboardView extends WI.DashboardView
>     {
>         super(representedObject, "default");
> 
>-        representedObject.addEventListener(WI.DefaultDashboard.Event.DataDidChange, () => { this._updateDisplaySoon(); });
>+        representedObject.addEventListener(WI.DefaultDashboard.Event.DataDidChange, function(event) {
>+            this._updateDisplaySoon();
>+        }, this);
>+
>         this._scheduledUpdateIdentifier = undefined;
> 
>         this._items = {
>diff --git a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotClassDataGridNode.js b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotClassDataGridNode.js
>index 5791ac1722d..85d9b257c18 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotClassDataGridNode.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotClassDataGridNode.js
>@@ -35,7 +35,7 @@ WI.HeapSnapshotClassDataGridNode = class HeapSnapshotClassDataGridNode extends W
>         this._batched = false;
>         this._instances = null;
> 
>-        this.addEventListener("populate", this._populate, this);
>+        this.addEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
>     }
> 
>     // Protected
>@@ -134,7 +134,7 @@ WI.HeapSnapshotClassDataGridNode = class HeapSnapshotClassDataGridNode extends W
> 
>     _populate()
>     {
>-        this.removeEventListener("populate", this._populate, this);
>+        this.removeEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
> 
>         this._tree.heapSnapshot.instancesWithClassName(this._data.className, (instances) => {
>             // FIXME: <https://webkit.org/b/157905> Web Inspector: Provide a way to toggle between showing only live objects and live+dead objects
>diff --git a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotContentView.js b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotContentView.js
>index 40096270ae8..bd37ae62e23 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotContentView.js
>@@ -37,7 +37,9 @@ WI.HeapSnapshotContentView = class HeapSnapshotContentView extends WI.ContentVie
>         this._exportButtonNavigationItem.tooltip = WI.UIString("Export (%s)").format(WI.saveKeyboardShortcut.displayName);
>         this._exportButtonNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
>         this._exportButtonNavigationItem.visibilityPriority = WI.NavigationItem.VisibilityPriority.High;
>-        this._exportButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => { this._exportSnapshot(); });
>+        this._exportButtonNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>+            this._exportSnapshot();
>+        }, this);
> 
>         this._dataGrid = new WI.DataGrid(columns);
>         this._dataGrid.sortColumnIdentifier = "retainedSize";
>diff --git a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotInstanceDataGridNode.js b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotInstanceDataGridNode.js
>index 54846f502be..e026f54c3e7 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotInstanceDataGridNode.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/HeapSnapshotInstanceDataGridNode.js
>@@ -45,7 +45,7 @@ WI.HeapSnapshotInstanceDataGridNode = class HeapSnapshotInstanceDataGridNode ext
>         this.copyable = false;
> 
>         if (hasChildren)
>-            this.addEventListener("populate", this._populate, this);
>+            this.addEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
>     }
> 
>     // Static
>@@ -218,7 +218,7 @@ WI.HeapSnapshotInstanceDataGridNode = class HeapSnapshotInstanceDataGridNode ext
> 
>     _populate()
>     {
>-        this.removeEventListener("populate", this._populate, this);
>+        this.removeEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
> 
>         function propertyName(edge) {
>             return edge ? WI.HeapSnapshotRootPath.pathComponentForIndividualEdge(edge) : "";
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ImageResourceContentView.js b/Source/WebInspectorUI/UserInterface/Views/ImageResourceContentView.js
>index 0a10de5a5dc..20954dd8864 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ImageResourceContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ImageResourceContentView.js
>@@ -72,20 +72,20 @@ WI.ImageResourceContentView = class ImageResourceContentView extends WI.Resource
> 
>     // Protected
> 
>-    shown()
>+    attached()
>     {
>-        super.shown();
>+        super.attached();
> 
>         this._updateImageGrid();
> 
>         WI.settings.showImageGrid.addEventListener(WI.Setting.Event.Changed, this._updateImageGrid, this);
>     }
> 
>-    hidden()
>+    detached()
>     {
>         WI.settings.showImageGrid.removeEventListener(WI.Setting.Event.Changed, this._updateImageGrid, this);
> 
>-        super.hidden();
>+        super.detached();
>     }
> 
>     // Private
>diff --git a/Source/WebInspectorUI/UserInterface/Views/InlineSwatch.js b/Source/WebInspectorUI/UserInterface/Views/InlineSwatch.js
>index 4de1fd4da8a..cd65bc76108 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/InlineSwatch.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/InlineSwatch.js
>@@ -185,13 +185,17 @@ WI.InlineSwatch = class InlineSwatch extends WI.Object
>         case WI.InlineSwatch.Type.Color:
>             this._valueEditor = new WI.ColorPicker;
>             this._valueEditor.addEventListener(WI.ColorPicker.Event.ColorChanged, this._valueEditorValueDidChange, this);
>-            this._valueEditor.addEventListener(WI.ColorPicker.Event.FormatChanged, (event) => popover.update());
>+            this._valueEditor.addEventListener(WI.ColorPicker.Event.FormatChanged, function(event) {
>+                popover.update();
>+            }, popover);
>             break;
> 
>         case WI.InlineSwatch.Type.Gradient:
>             this._valueEditor = new WI.GradientEditor;
>             this._valueEditor.addEventListener(WI.GradientEditor.Event.GradientChanged, this._valueEditorValueDidChange, this);
>-            this._valueEditor.addEventListener(WI.GradientEditor.Event.ColorPickerToggled, (event) => popover.update());
>+            this._valueEditor.addEventListener(WI.GradientEditor.Event.ColorPickerToggled, function(event) {
>+                popover.update();
>+            }, popover);
>             break;
> 
>         case WI.InlineSwatch.Type.Bezier:
>diff --git a/Source/WebInspectorUI/UserInterface/Views/LogContentView.js b/Source/WebInspectorUI/UserInterface/Views/LogContentView.js
>index 35924ae386b..ca15ad5e913 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/LogContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/LogContentView.js
>@@ -70,16 +70,16 @@ WI.LogContentView = class LogContentView extends WI.ContentView
> 
>         this._preserveLogNavigationItem = new WI.CheckboxNavigationItem("preserve-log", WI.UIString("Preserve Log"), !WI.settings.clearLogOnNavigate.value);
>         this._preserveLogNavigationItem.tooltip = WI.UIString("Do not clear the console on new page loads");
>-        this._preserveLogNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, () => {
>+        this._preserveLogNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, function(event) {
>             WI.settings.clearLogOnNavigate.value = !WI.settings.clearLogOnNavigate.value;
>-        });
>+        }, WI);
>         WI.settings.clearLogOnNavigate.addEventListener(WI.Setting.Event.Changed, this._handleClearLogOnNavigateSettingChanged, this);
> 
>         this._emulateInUserGestureNavigationItem = new WI.CheckboxNavigationItem("emulate-in-user-gesture", WI.UIString("Emulate User Gesture"), WI.settings.emulateInUserGesture.value);
>         this._emulateInUserGestureNavigationItem.tooltip = WI.UIString("Run console commands as if inside a user gesture");
>-        this._emulateInUserGestureNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, () => {
>+        this._emulateInUserGestureNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, function(event) {
>             WI.settings.emulateInUserGesture.value = !WI.settings.emulateInUserGesture.value;
>-        });
>+        }, WI);
>         WI.settings.emulateInUserGesture.addEventListener(WI.Setting.Event.Changed, this._handleEmulateInUserGestureSettingChanged, this);
> 
>         this._checkboxesNavigationItemGroup = new WI.GroupNavigationItem([this._preserveLogNavigationItem, this._emulateInUserGestureNavigationItem, new WI.DividerNavigationItem]);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/NetworkTableContentView.js b/Source/WebInspectorUI/UserInterface/Views/NetworkTableContentView.js
>index 872eab8441e..9dac9b6b801 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/NetworkTableContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/NetworkTableContentView.js
>@@ -108,22 +108,24 @@ WI.NetworkTableContentView = class NetworkTableContentView extends WI.ContentVie
> 
>         this._clearOnLoadNavigationItem = new WI.CheckboxNavigationItem("preserve-log", WI.UIString("Preserve Log"), !WI.settings.clearNetworkOnNavigate.value);
>         this._clearOnLoadNavigationItem.tooltip = WI.UIString("Do not clear network items on new page loads");
>-        this._clearOnLoadNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, () => { WI.settings.clearNetworkOnNavigate.value = !WI.settings.clearNetworkOnNavigate.value; });
>+        this._clearOnLoadNavigationItem.addEventListener(WI.CheckboxNavigationItem.Event.CheckedDidChange, function(event) {
>+            WI.settings.clearNetworkOnNavigate.value = !WI.settings.clearNetworkOnNavigate.value;
>+        }, WI);
>         WI.settings.clearNetworkOnNavigate.addEventListener(WI.Setting.Event.Changed, this._clearNetworkOnNavigateSettingChanged, this);
> 
>         this._harImportNavigationItem = new WI.ButtonNavigationItem("har-import", WI.UIString("Import"), "Images/Import.svg", 15, 15);
>         this._harImportNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
>         this._harImportNavigationItem.tooltip = WI.UIString("HAR Import");
>-        this._harImportNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+        this._harImportNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>             this._importHAR();
>-        });
>+        }, this);
> 
>         this._harExportNavigationItem = new WI.ButtonNavigationItem("har-export", WI.UIString("Export"), "Images/Export.svg", 15, 15);
>         this._harExportNavigationItem.buttonStyle = WI.ButtonNavigationItem.Style.ImageAndText;
>         this._harExportNavigationItem.tooltip = WI.UIString("HAR Export (%s)").format(WI.saveKeyboardShortcut.displayName);
>-        this._harExportNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+        this._harExportNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>             this._exportHAR();
>-        });
>+        }, this);
> 
>         this._collectionsPathNavigationItem = new WI.HierarchicalPathNavigationItem;
>         this._collectionsPathNavigationItem.addEventListener(WI.HierarchicalPathNavigationItem.Event.PathComponentWasSelected, this._collectionsHierarchicalPathComponentWasSelected, this);
>@@ -155,9 +157,9 @@ WI.NetworkTableContentView = class NetworkTableContentView extends WI.ContentVie
>         }
> 
>         this._clearNetworkItemsNavigationItem = new WI.ButtonNavigationItem("clear-network-items", WI.UIString("Clear Network Items (%s)").format(WI.clearKeyboardShortcut.displayName), "Images/NavigationItemTrash.svg", 15, 15);
>-        this._clearNetworkItemsNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, () => {
>+        this._clearNetworkItemsNavigationItem.addEventListener(WI.ButtonNavigationItem.Event.Clicked, function(event) {
>             this.reset();
>-        });
>+        }, this);
> 
>         WI.Target.addEventListener(WI.Target.Event.ResourceAdded, this._handleResourceAdded, this);
>         WI.Frame.addEventListener(WI.Frame.Event.MainResourceDidChange, this._mainResourceDidChange, this);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ProfileDataGridNode.js b/Source/WebInspectorUI/UserInterface/Views/ProfileDataGridNode.js
>index e29449e1b1f..1dd7e8ce924 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ProfileDataGridNode.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ProfileDataGridNode.js
>@@ -38,7 +38,7 @@ WI.ProfileDataGridNode = class ProfileDataGridNode extends WI.DataGridNode
>         // FIXME: Make profile data grid nodes copyable.
>         this.copyable = false;
> 
>-        this.addEventListener("populate", this._populate, this);
>+        this.addEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
> 
>         this._updateChildrenForModifiers();
>         this._recalculateData();
>@@ -258,7 +258,7 @@ WI.ProfileDataGridNode = class ProfileDataGridNode extends WI.DataGridNode
>         if (!this.shouldRefreshChildren)
>             return;
> 
>-        this.removeEventListener("populate", this._populate, this);
>+        this.removeEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
> 
>         this._node.forEachChild((child) => {
>             if (!this._childrenToChargeToSelf.has(child)) {
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ProfileNodeDataGridNode.js b/Source/WebInspectorUI/UserInterface/Views/ProfileNodeDataGridNode.js
>index 3d3969c1c17..20da878d3e5 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ProfileNodeDataGridNode.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ProfileNodeDataGridNode.js
>@@ -35,7 +35,7 @@ WI.ProfileNodeDataGridNode = class ProfileNodeDataGridNode extends WI.TimelineDa
> 
>         this._profileNode = profileNode;
> 
>-        this.addEventListener("populate", this._populate, this);
>+        this.addEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
>     }
> 
>     // Public
>@@ -140,7 +140,7 @@ WI.ProfileNodeDataGridNode = class ProfileNodeDataGridNode extends WI.TimelineDa
>         if (!this.shouldRefreshChildren)
>             return;
> 
>-        this.removeEventListener("populate", this._populate, this);
>+        this.removeEventListener(WI.DataGridNode.Event.Populate, this._populate, this);
>         this.removeChildren();
> 
>         for (let node of this._profileNode.childNodes)
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ResourceDetailsSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/ResourceDetailsSidebarPanel.js
>index 759e5d65874..162dcfef4b3 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ResourceDetailsSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ResourceDetailsSidebarPanel.js
>@@ -621,7 +621,7 @@ WI.ResourceDetailsSidebarPanel = class ResourceDetailsSidebarPanel extends WI.De
>         this._resource.addEventListener(WI.Resource.Event.MetricsDidChange, this._refreshRequestAndResponse, this);
>         this._resource.addEventListener(WI.Resource.Event.SizeDidChange, this._refreshDecodedSize, this);
>         this._resource.addEventListener(WI.Resource.Event.TransferSizeDidChange, this._refreshTransferSize, this);
>-        this._resource.addEventListener(WI.Resource.Event.InitiatedResourcesDidChange, () => {
>+        this._resource.addEventListener(WI.Resource.Event.InitiatedResourcesDidChange, function(event) {
>             this._refreshRelatedResourcesSectionThrottler.fire();
>         }, this);
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ResourceSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/ResourceSidebarPanel.js
>index 7b1d61025f8..3718be17510 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ResourceSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ResourceSidebarPanel.js
>@@ -70,7 +70,9 @@ WI.ResourceSidebarPanel = class ResourceSidebarPanel extends WI.NavigationSideba
> 
>         if (ResourceSidebarPanel.shouldPlaceResourcesAtTopLevel()) {
>             this.contentTreeOutline.disclosureButtons = false;
>-            WI.SourceCode.addEventListener(WI.SourceCode.Event.SourceMapAdded, () => { this.contentTreeOutline.disclosureButtons = true; }, this);
>+            WI.SourceCode.addEventListener(WI.SourceCode.Event.SourceMapAdded, function(event) {
>+                this.contentTreeOutline.disclosureButtons = true;
>+            }, this);
>         }
>     }
> 
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ScopeChainDetailsSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/ScopeChainDetailsSidebarPanel.js
>index eb2ff6fc6a9..5c34988009e 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ScopeChainDetailsSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ScopeChainDetailsSidebarPanel.js
>@@ -262,8 +262,12 @@ WI.ScopeChainDetailsSidebarPanel = class ScopeChainDetailsSidebarPanel extends W
> 
>                 let treeOutline = objectTree.treeOutline;
>                 treeOutline.registerScrollVirtualizer(this.contentView.element, 16);
>-                treeOutline.addEventListener(WI.TreeOutline.Event.ElementAdded, this._treeElementAdded.bind(this, detailsSectionIdentifier), this);
>-                treeOutline.addEventListener(WI.TreeOutline.Event.ElementDisclosureDidChanged, this._treeElementDisclosureDidChange.bind(this, detailsSectionIdentifier), this);
>+                treeOutline.addEventListener(WI.TreeOutline.Event.ElementAdded, function(event) {
>+                    this._treeElementAdded(detailsSectionIdentifier, event);
>+                }, this);
>+                treeOutline.addEventListener(WI.TreeOutline.Event.ElementDisclosureDidChanged, function(event) {
>+                    this._treeElementDisclosureDidChange(detailsSectionIdentifier, event);
>+                }, this);
> 
>                 rows.push(new WI.ObjectPropertiesDetailSectionRow(objectTree, detailsSection));
>             }
>@@ -298,8 +302,12 @@ WI.ScopeChainDetailsSidebarPanel = class ScopeChainDetailsSidebarPanel extends W
> 
>         let treeOutline = objectTree.treeOutline;
>         const watchExpressionSectionIdentifier = "watch-expressions";
>-        treeOutline.addEventListener(WI.TreeOutline.Event.ElementAdded, this._treeElementAdded.bind(this, watchExpressionSectionIdentifier), this);
>-        treeOutline.addEventListener(WI.TreeOutline.Event.ElementDisclosureDidChanged, this._treeElementDisclosureDidChange.bind(this, watchExpressionSectionIdentifier), this);
>+        treeOutline.addEventListener(WI.TreeOutline.Event.ElementAdded, function(event) {
>+            this._treeElementAdded(watchExpressionSectionIdentifier, event);
>+        }, this);
>+        treeOutline.addEventListener(WI.TreeOutline.Event.ElementDisclosureDidChanged, function(event) {
>+            this._treeElementDisclosureDidChange(watchExpressionSectionIdentifier, event);
>+        }, this);
>         treeOutline.objectTreeElementAddContextMenuItems = this._objectTreeElementAddContextMenuItems.bind(this);
> 
>         let promises = [];
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SearchSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/SearchSidebarPanel.js
>index fb1b3d12f54..7e9673b3a79 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SearchSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SearchSidebarPanel.js
>@@ -29,11 +29,12 @@ WI.SearchSidebarPanel = class SearchSidebarPanel extends WI.NavigationSidebarPan
>     {
>         super("search", WI.UIString("Search"), true, true);
> 
>-        this._searchInputSettings = WI.SearchUtilities.createSettings("search-sidebar", {
>-            handleChanged: (event) => {
>+        this._searchInputSettings = WI.SearchUtilities.createSettings("search-sidebar");
>+        for (let setting of Object.values(this._searchInputSettings)) {
>+            setting.addEventListener(WI.Setting.Event.Changed, function(event) {
>                 this.focusSearchField(true);
>-            },
>-        });
>+            }, this);
>+        }
> 
>         var searchElement = document.createElement("div");
>         searchElement.classList.add("search-bar");
>@@ -206,8 +207,8 @@ WI.SearchSidebarPanel = class SearchSidebarPanel extends WI.NavigationSidebarPan
>             }
> 
>             let promises = [
>-                WI.Frame.awaitEvent(WI.Frame.Event.ResourceWasAdded),
>-                WI.Target.awaitEvent(WI.Target.Event.ResourceAdded)
>+                WI.Frame.awaitEvent(WI.Frame.Event.ResourceWasAdded, this),
>+                WI.Target.awaitEvent(WI.Target.Event.ResourceAdded, this),
>             ];
>             Promise.race(promises).then(this._contentChanged.bind(this));
>         };
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SettingEditor.js b/Source/WebInspectorUI/UserInterface/Views/SettingEditor.js
>index 648baa6b14a..1853d5da452 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SettingEditor.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SettingEditor.js
>@@ -56,8 +56,12 @@ WI.SettingEditor = class SettingEditor extends WI.Object
> 
>         let editor = new WI.SettingEditor(type, label, options);
>         editor.value = setting.value;
>-        editor.addEventListener(WI.SettingEditor.Event.ValueDidChange, () => { setting.value = editor.value; });
>-        setting.addEventListener(WI.Setting.Event.Changed, () => { editor.value = setting.value; });
>+        editor.addEventListener(WI.SettingEditor.Event.ValueDidChange, function(event) {
>+            setting.value = editor.value;
>+        }, setting);
>+        setting.addEventListener(WI.Setting.Event.Changed, function(event) {
>+            editor.value = setting.value;
>+        }, editor);
> 
>         return editor;
>     }
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SettingsTabContentView.js b/Source/WebInspectorUI/UserInterface/Views/SettingsTabContentView.js
>index 14aadeddc05..0250a4d7535 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SettingsTabContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SettingsTabContentView.js
>@@ -182,9 +182,9 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
>         const indentValues = [WI.UIString("Tabs"), WI.UIString("Spaces")];
>         let indentEditor = generalSettingsView.addGroupWithCustomSetting(WI.UIString("Prefer indent using:"), WI.SettingEditor.Type.Select, {values: indentValues});
>         indentEditor.value = indentValues[WI.settings.indentWithTabs.value ? 0 : 1];
>-        indentEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, () => {
>+        indentEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, function(event) {
>             WI.settings.indentWithTabs.value = indentEditor.value === indentValues[0];
>-        });
>+        }, WI);
> 
>         function addSpacesSetting(title, setting) {
>             let editor = generalSettingsView.addSetting(title, setting, WI.UIString("spaces"), {min: 1});
>@@ -192,9 +192,9 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
>             function updateLabel() {
>                 editor.label = setting.value === 1 ? WI.UIString("space") : WI.UIString("spaces");
>             }
>-            setting.addEventListener(WI.Setting.Event.Changed, (event) => {
>+            setting.addEventListener(WI.Setting.Event.Changed, function(event) {
>                 updateLabel();
>-            });
>+            }, editor);
>             updateLabel();
>         }
>         addSpacesSetting(WI.UIString("Tab width:"), WI.settings.tabSize);
>@@ -219,8 +219,12 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
> 
>         let zoomEditor = generalSettingsView.addGroupWithCustomSetting(WI.UIString("Zoom:"), WI.SettingEditor.Type.Select, {values: zoomValues});
>         zoomEditor.value = WI.getZoomFactor();
>-        zoomEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, () => { WI.setZoomFactor(zoomEditor.value); });
>-        WI.settings.zoomFactor.addEventListener(WI.Setting.Event.Changed, () => { zoomEditor.value = WI.getZoomFactor().maxDecimals(2); });
>+        zoomEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, function(event) {
>+            WI.setZoomFactor(zoomEditor.value);
>+        }, WI);
>+        WI.settings.zoomFactor.addEventListener(WI.Setting.Event.Changed, function(event) {
>+            zoomEditor.value = WI.getZoomFactor().maxDecimals(2);
>+        }, zoomEditor);
> 
>         this.addSettingsView(generalSettingsView);
>     }
>@@ -280,10 +284,10 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
>             for (let channel of channels) {
>                 let logEditor = consoleSettingsView.addGroupWithCustomSetting(editorLabels[channel.source], WI.SettingEditor.Type.Select, {values: logLevels});
>                 logEditor.value = channel.level;
>-                logEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, () => {
>+                logEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, function(event) {
>                     for (let target of WI.targets)
>                         target.ConsoleAgent.setLoggingChannelLevel(channel.source, logEditor.value);
>-                });
>+                }, WI);
>             }
>         }
> 
>@@ -329,9 +333,9 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
> 
>         function listenForChange(setting) {
>             initialValues.set(setting, setting.value);
>-            setting.addEventListener(WI.Setting.Event.Changed, () => {
>+            setting.addEventListener(WI.Setting.Event.Changed, function(event) {
>                 reloadInspectorContainerElement.classList.toggle("hidden", Array.from(initialValues).every(([setting, initialValue]) => setting.value === initialValue));
>-            });
>+            }, reloadInspectorContainerElement);
>         }
> 
>         listenForChange(WI.settings.experimentalEnableSourcesTab);
>@@ -354,9 +358,9 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
>         let protocolMessagesGroup = this._debugSettingsView.addGroup(WI.unlocalizedString("Protocol Logging:"));
> 
>         let autoLogProtocolMessagesEditor = protocolMessagesGroup.addSetting(WI.settings.autoLogProtocolMessages, WI.unlocalizedString("Messages"));
>-        WI.settings.autoLogProtocolMessages.addEventListener(WI.Setting.Event.Changed, () => {
>+        WI.settings.autoLogProtocolMessages.addEventListener(WI.Setting.Event.Changed, function(event) {
>             autoLogProtocolMessagesEditor.value = InspectorBackend.dumpInspectorProtocolMessages;
>-        });
>+        }, autoLogProtocolMessagesEditor);
> 
>         protocolMessagesGroup.addSetting(WI.settings.autoLogTimeStats, WI.unlocalizedString("Time Stats"));
> 
>@@ -388,7 +392,9 @@ WI.SettingsTabContentView = class SettingsTabContentView extends WI.TabContentVi
> 
>         let layoutDirectionEditor = this._debugSettingsView.addGroupWithCustomSetting(WI.unlocalizedString("Layout Direction:"), WI.SettingEditor.Type.Select, {values: layoutDirectionValues});
>         layoutDirectionEditor.value = WI.settings.layoutDirection.value;
>-        layoutDirectionEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, () => { WI.setLayoutDirection(layoutDirectionEditor.value); });
>+        layoutDirectionEditor.addEventListener(WI.SettingEditor.Event.ValueDidChange, function(event) {
>+            WI.setLayoutDirection(layoutDirectionEditor.value);
>+        }, WI);
> 
>         let resetInspectorButton = document.createElement("button");
>         resetInspectorButton.textContent = WI.unlocalizedString("Reset Web Inspector");
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ShaderProgramContentView.js b/Source/WebInspectorUI/UserInterface/Views/ShaderProgramContentView.js
>index dd9254ed5be..a0d2319f088 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ShaderProgramContentView.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ShaderProgramContentView.js
>@@ -42,9 +42,9 @@ WI.ShaderProgramContentView = class ShaderProgramContentView extends WI.ContentV
>             textEditor.readOnly = false;
>             textEditor.addEventListener(WI.TextEditor.Event.Focused, this._editorFocused, this);
>             textEditor.addEventListener(WI.TextEditor.Event.NumberOfSearchResultsDidChange, this._numberOfSearchResultsDidChange, this);
>-            textEditor.addEventListener(WI.TextEditor.Event.ContentDidChange, (event) => {
>+            textEditor.addEventListener(WI.TextEditor.Event.ContentDidChange, function(event) {
>                 contentDidChangeDebouncer.delayForTime(250, event);
>-            }, this);
>+            }, contentDidChangeDebouncer);
>             textEditor.element.classList.add("shader");
> 
>             let shaderTypeContainer = textEditor.element.insertAdjacentElement("afterbegin", document.createElement("div"));
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SourcesNavigationSidebarPanel.js b/Source/WebInspectorUI/UserInterface/Views/SourcesNavigationSidebarPanel.js
>index 1bd1dc6bc6e..ac8ded0d458 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SourcesNavigationSidebarPanel.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SourcesNavigationSidebarPanel.js
>@@ -296,7 +296,7 @@ WI.SourcesNavigationSidebarPanel = class SourcesNavigationSidebarPanel extends W
> 
>         if (WI.SourcesNavigationSidebarPanel.shouldPlaceResourcesAtTopLevel()) {
>             this._resourcesTreeOutline.disclosureButtons = false;
>-            WI.SourceCode.addEventListener(WI.SourceCode.Event.SourceMapAdded, () => {
>+            WI.SourceCode.addEventListener(WI.SourceCode.Event.SourceMapAdded, function(event) {
>                 this._resourcesTreeOutline.disclosureButtons = true;
>             }, this);
>         }
>@@ -476,9 +476,9 @@ WI.SourcesNavigationSidebarPanel = class SourcesNavigationSidebarPanel extends W
> 
>     createContentTreeOutline(options = {})
>     {
>-        let treeOutline = super.createContentTreeOutline(options)
>+        let treeOutline = super.createContentTreeOutline(options);
> 
>-        treeOutline.addEventListener(WI.TreeOutline.Event.ElementRevealed, (event) => {
>+        treeOutline.addEventListener(WI.TreeOutline.Event.ElementRevealed, function(event) {
>             let treeElement = event.data.element;
>             let detailsSections = [this._pauseReasonSection, this._callStackSection, this._breakpointsSection];
>             let detailsSection = detailsSections.find((detailsSection) => detailsSection.element.contains(treeElement.listItemElement));
>@@ -492,7 +492,7 @@ WI.SourcesNavigationSidebarPanel = class SourcesNavigationSidebarPanel extends W
>             let offset = detailsSection.headerElement.totalOffsetBottom - treeElement.listItemElement.totalOffsetTop;
>             if (offset > 0)
>                 this.scrollElement.scrollBy(0, -offset);
>-        });
>+        }, this);
> 
>         return treeOutline;
>     }
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SpreadsheetCSSStyleDeclarationSection.js b/Source/WebInspectorUI/UserInterface/Views/SpreadsheetCSSStyleDeclarationSection.js
>index fecbe60c23f..9ae0954b98a 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SpreadsheetCSSStyleDeclarationSection.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SpreadsheetCSSStyleDeclarationSection.js
>@@ -81,12 +81,12 @@ WI.SpreadsheetCSSStyleDeclarationSection = class SpreadsheetCSSStyleDeclarationS
> 
>         if (this._style.selectorEditable) {
>             this._selectorTextField = new WI.SpreadsheetSelectorField(this, this._selectorElement);
>-            this._selectorTextField.addEventListener(WI.SpreadsheetSelectorField.Event.StartedEditing, (event) => {
>+            this._selectorTextField.addEventListener(WI.SpreadsheetSelectorField.Event.StartedEditing, function(event) {
>                 this._headerElement.classList.add("editing-selector");
>-            });
>-            this._selectorTextField.addEventListener(WI.SpreadsheetSelectorField.Event.StoppedEditing, (event) => {
>+            }, this);
>+            this._selectorTextField.addEventListener(WI.SpreadsheetSelectorField.Event.StoppedEditing, function(event) {
>                 this._headerElement.classList.remove("editing-selector");
>-            });
>+            }, this);
> 
>             this._selectorElement.tabIndex = 0;
>         }
>diff --git a/Source/WebInspectorUI/UserInterface/Views/SpreadsheetStyleProperty.js b/Source/WebInspectorUI/UserInterface/Views/SpreadsheetStyleProperty.js
>index 6cbc629b264..227b3327830 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/SpreadsheetStyleProperty.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/SpreadsheetStyleProperty.js
>@@ -511,7 +511,7 @@ WI.SpreadsheetStyleProperty = class SpreadsheetStyleProperty extends WI.Object
>         let readOnly = !this._isEditable();
>         let swatch = new WI.InlineSwatch(type, valueObject, readOnly);
> 
>-        swatch.addEventListener(WI.InlineSwatch.Event.ValueChanged, (event) => {
>+        swatch.addEventListener(WI.InlineSwatch.Event.ValueChanged, function(event) {
>             let value = event.data.value && event.data.value.toString();
>             if (!value)
>                 return;
>@@ -524,15 +524,15 @@ WI.SpreadsheetStyleProperty = class SpreadsheetStyleProperty extends WI.Object
>         }, this);
> 
>         if (this._delegate && typeof this._delegate.stylePropertyInlineSwatchActivated === "function") {
>-            swatch.addEventListener(WI.InlineSwatch.Event.Activated, () => {
>+            swatch.addEventListener(WI.InlineSwatch.Event.Activated, function(event) {
>                 this._delegate.stylePropertyInlineSwatchActivated();
>-            });
>+            }, this);
>         }
> 
>         if (this._delegate && typeof this._delegate.stylePropertyInlineSwatchDeactivated === "function") {
>-            swatch.addEventListener(WI.InlineSwatch.Event.Deactivated, () => {
>+            swatch.addEventListener(WI.InlineSwatch.Event.Deactivated, function(event) {
>                 this._delegate.stylePropertyInlineSwatchDeactivated();
>-            });
>+            }, this);
>         }
> 
>         tokenElement.append(swatch.element, innerElement);
>diff --git a/Source/WebInspectorUI/UserInterface/Views/ThreadTreeElement.js b/Source/WebInspectorUI/UserInterface/Views/ThreadTreeElement.js
>index e81e97ed74b..7a1dc1fb084 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/ThreadTreeElement.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/ThreadTreeElement.js
>@@ -141,7 +141,9 @@ WI.ThreadTreeElement = class ThreadTreeElement extends WI.GeneralTreeElement
>         if (!this._statusButton) {
>             let tooltip = WI.UIString("Resume Thread");
>             this._statusButton = new WI.TreeElementStatusButton(WI.ImageUtilities.useSVGSymbol("Images/Resume.svg", "resume", tooltip));
>-            this._statusButton.addEventListener(WI.TreeElementStatusButton.Event.Clicked, () => { WI.debuggerManager.continueUntilNextRunLoop(this._target); });
>+            this._statusButton.addEventListener(WI.TreeElementStatusButton.Event.Clicked, function(event) {
>+                WI.debuggerManager.continueUntilNextRunLoop(this._target);
>+            }, this);
>             this._statusButton.element.addEventListener("mousedown", (event) => {
>                 // Prevent tree element from being selected.
>                 event.stopPropagation();
>diff --git a/Source/WebInspectorUI/UserInterface/Views/TimelineTreeElement.js b/Source/WebInspectorUI/UserInterface/Views/TimelineTreeElement.js
>index 94a07133218..b93d4992532 100644
>--- a/Source/WebInspectorUI/UserInterface/Views/TimelineTreeElement.js
>+++ b/Source/WebInspectorUI/UserInterface/Views/TimelineTreeElement.js
>@@ -76,8 +76,9 @@ WI.TimelineTreeElement = class TimelineTreeElement extends WI.GeneralTreeElement
>     {
>         let tooltip = WI.UIString("Close %s timeline view").format(this.mainTitle);
>         let button = new WI.TreeElementStatusButton(WI.ImageUtilities.useSVGSymbol("Images/CloseLarge.svg", "close-button", tooltip));
>-        button.addEventListener(WI.TreeElementStatusButton.Event.Clicked, () => { this.deselect(); });
>-
>+        button.addEventListener(WI.TreeElementStatusButton.Event.Clicked, function(event) {
>+            this.deselect();
>+        }, this);
>         this.status = button.element;
>     }
> 
>@@ -86,10 +87,9 @@ WI.TimelineTreeElement = class TimelineTreeElement extends WI.GeneralTreeElement
>         let checkboxElement = document.createElement("input");
>         checkboxElement.type = "checkbox";
>         checkboxElement.checked = !this._placeholder;
>-
>-        let button = new WI.TreeElementStatusButton(checkboxElement);
>-        checkboxElement.addEventListener("change", () => { this._dispatchEnabledDidChangeEvent(); });
>-
>+        checkboxElement.addEventListener("change", (event) => {
>+            this._dispatchEnabledDidChangeEvent();
>+        });
>         this.status = checkboxElement;
>     }
>

Flags:

hi: commit-queue-

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Attachments on bug 196956: 367502 | 367517 | 367523 | 367527 | 367568 | 372431 | 372436 | 372441 | 372477 | 372530 | 376656 | 376661 | 376662 | 411024 | 411030 | 413134 | 413142 | 413341