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

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef OffscreenCanvasFrameDispatcherImpl_h
 #define OffscreenCanvasFrameDispatcherImpl_h
 
 #include "cc/ipc/mojo_compositor_frame_sink.mojom-blink.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/resources/shared_bitmap.h"
@@ skipping 14 matching lines @@
  public:
   OffscreenCanvasFrameDispatcherImpl(OffscreenCanvasFrameDispatcherClient*,
                                      uint32_t clientId,
                                      uint32_t sinkId,
                                      int canvasId,
                                      int width,
                                      int height);
 
   // OffscreenCanvasFrameDispatcher implementation.
   ~OffscreenCanvasFrameDispatcherImpl() final;
+  void setNeedsBeginFrame(bool) final;
   void dispatchFrame(RefPtr<StaticBitmapImage>,
                      double commitStartTime,
                      bool isWebGLSoftwareRendering = false) final;
   void reclaimResource(unsigned resourceId) final;
   void reshape(int width, int height) final;
 
   // cc::mojom::blink::MojoCompositorFrameSinkClient implementation.
   void DidReceiveCompositorFrameAck() final;
   void OnBeginFrame(const cc::BeginFrameArgs&) final;
   void ReclaimResources(const cc::ReturnedResourceArray& resources) final;
   void WillDrawSurface() final;
 
   // This enum is used in histogram, so it should be append-only.
   enum OffscreenCanvasCommitType {
     CommitGPUCanvasGPUCompositing = 0,
     CommitGPUCanvasSoftwareCompositing = 1,
     CommitSoftwareCanvasGPUCompositing = 2,
     CommitSoftwareCanvasSoftwareCompositing = 3,
     OffscreenCanvasCommitTypeCount,
   };
 
  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;
   HashMap<unsigned, std::unique_ptr<cc::SharedBitmap>> m_sharedBitmaps;
   HashMap<unsigned, GLuint> m_cachedTextureIds;
   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;
 
   int m_placeholderCanvasId;
 
   void setTransferableResourceToSharedBitmap(cc::TransferableResource&,
                                              RefPtr<StaticBitmapImage>);
   void setTransferableResourceToSharedGPUContext(cc::TransferableResource&,
                                                  RefPtr<StaticBitmapImage>);
   void setTransferableResourceToStaticBitmapImage(cc::TransferableResource&,
                                                   RefPtr<StaticBitmapImage>);
 };
 
 }  // namespace blink
 
 #endif  // OffscreenCanvasFrameDispatcherImpl_h