Bug 148493

The recent switch to WTF::Lock results in build failures with ENABLE_THREADED_COMPOSITOR=ON: ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp: In member function ‘void WebKit::ThreadedCompositor::createCompositingThread()’: ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:301:72: error: no matching function for call to ‘WTF::ThreadCondition::wait(WTF::Lock&)’ m_initializeRunLoopCondition.wait(m_initializeRunLoopConditionMutex); ^ ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:301:72: note: candidate is: In file included from ../../Source/WTF/wtf/Threading.h:44:0, from ../../Source/WebCore/platform/Timer.h:32, from ../../Source/WebCore/platform/graphics/FontCache.h:34, from ../../Source/WebCore/platform/graphics/freetype/FontPlatformData.h:29, from ../../Source/WebCore/platform/graphics/FontPlatformData.h:27, from ../../Source/WebCore/platform/graphics/Font.h:30, from ../../Source/WebCore/platform/graphics/FontCascade.h:29, from ../../Source/WebCore/platform/graphics/GraphicsContext.h:33, from DerivedSources/ForwardingHeaders/WebCore/GraphicsContext.h:1, from ../../Source/WebKit2/Shared/CoordinatedGraphics/CoordinatedGraphicsScene.h:27, from ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.h:31, from ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:29: ../../Source/WTF/wtf/ThreadingPrimitives.h:97:10: note: void WTF::ThreadCondition::wait(WTF::Mutex&) WTF_EXPORT_PRIVATE void wait(Mutex& mutex); ^ ../../Source/WTF/wtf/ThreadingPrimitives.h:97:10: note: no known conversion for argument 1 from ‘WTF::Lock’ to ‘WTF::Mutex&’ ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp: In member function ‘void WebKit::ThreadedCompositor::terminateCompositingThread()’: ../../Source/WebKit2/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:340:70: error: no matching function for call to ‘WTF::ThreadCondition::wait(WTF::Lock&)’ m_terminateRunLoopCondition.wait(m_terminateRunLoopConditionMutex);