Make OffscreenCanvas animation in sync with its placeholder canvas's parent frame rate

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h

Index: third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h
diff --git a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h
index 8fe5f43b2ca632383c73d3e0d4f0fe3ada8d68d4..cb197b7ad5a306566dac7445690e8f4cddfd4f5d 100644
--- a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h
+++ b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.h
@@ -32,6 +32,7 @@ class PLATFORM_EXPORT OffscreenCanvasFrameDispatcherImpl final
 
   // OffscreenCanvasFrameDispatcher implementation.
   ~OffscreenCanvasFrameDispatcherImpl() final;
+  void setNeedsBeginFrame(bool) final;
   void dispatchFrame(RefPtr<StaticBitmapImage>,
                      double commitStartTime,
                      bool isWebGLSoftwareRendering = false) final;
@@ -56,15 +57,13 @@ class PLATFORM_EXPORT OffscreenCanvasFrameDispatcherImpl final
  private:
   // Surface-related
   cc::SurfaceIdAllocator m_surfaceIdAllocator;
-  void scheduleSyntheticBeginFrame();  // To be removed (crbug.com/674744)
-
-  TaskHandle m_syntheticBeginFrameTask;  // To be removed (crbug.com/674744)
   const cc::FrameSinkId m_frameSinkId;
   cc::LocalSurfaceId m_currentLocalSurfaceId;
 
   int m_width;
   int m_height;
   bool m_changeSizeForNextCommit;
+  bool m_needsBeginFrame;
 
   unsigned m_nextResourceId;
   HashMap<unsigned, RefPtr<StaticBitmapImage>> m_cachedImages;
@@ -73,6 +72,7 @@ class PLATFORM_EXPORT OffscreenCanvasFrameDispatcherImpl final
   HashSet<unsigned> m_spareResourceLocks;
 
   bool verifyImageSize(const IntSize);
+  void postImageToPlaceholder(RefPtr<StaticBitmapImage>);
 
   cc::mojom::blink::MojoCompositorFrameSinkPtr m_sink;
   mojo::Binding<cc::mojom::blink::MojoCompositorFrameSinkClient> m_binding;