compositor-worker: Add CompositorProxyClient worker client of CompositorWorker.

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 2359 matching lines @@
             'dom/ClassCollection.cpp',
             'dom/ClassCollection.h',
             'dom/ClientRect.cpp',
             'dom/ClientRect.h',
             'dom/ClientRectList.cpp',
             'dom/ClientRectList.h',
             'dom/Comment.cpp',
             'dom/Comment.h',
             'dom/CompositorProxy.cpp',
             'dom/CompositorProxy.h',
+            'dom/CompositorProxyClient.cpp',
+            'dom/CompositorProxyClient.h',
             'dom/ContainerNode.cpp',
             'dom/ContextFeatures.cpp',
             'dom/ContextFeatures.h',
             'dom/ContextLifecycleNotifier.cpp',
             'dom/ContextLifecycleNotifier.h',
             'dom/ContextLifecycleObserver.h',
             'dom/CrossThreadTask.h',
             'dom/DOMArrayBuffer.cpp',
             'dom/DOMArrayBuffer.h',
             'dom/DOMArrayBufferBase.h',
@@ skipping 1730 matching lines @@
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }