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

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcher.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 OffscreenCanvasFrameDispatcher_h
 #define OffscreenCanvasFrameDispatcher_h
 
 #include "platform/PlatformExport.h"
 #include "platform/WebTaskRunner.h"
 #include "wtf/RefPtr.h"
 #include "wtf/WeakPtr.h"
 
 namespace blink {
 
 class StaticBitmapImage;
 
 class OffscreenCanvasFrameDispatcherClient {
  public:
   virtual void beginFrame() = 0;
 };
 
 class PLATFORM_EXPORT OffscreenCanvasFrameDispatcher {
  public:
   virtual ~OffscreenCanvasFrameDispatcher() {}
   virtual void dispatchFrame(RefPtr<StaticBitmapImage>,
                              double commitStartTime,
                              bool isWebGLSoftwareRendering) = 0;
+  virtual void setNeedsBeginFrame(bool) = 0;
   virtual void reclaimResource(unsigned resourceId) = 0;
 
   virtual void reshape(int width, int height) = 0;
 
   WeakPtr<OffscreenCanvasFrameDispatcher> createWeakPtr() {
     return m_weakPtrFactory.createWeakPtr();
   }
 
   OffscreenCanvasFrameDispatcherClient* client() { return m_client; }
 
  protected:
   OffscreenCanvasFrameDispatcher(OffscreenCanvasFrameDispatcherClient* client)
       : m_weakPtrFactory(this), m_client(client) {}
 
  private:
   WeakPtrFactory<OffscreenCanvasFrameDispatcher> m_weakPtrFactory;
   OffscreenCanvasFrameDispatcherClient* m_client;
 };
 
 }  // namespace blink
 
 #endif  // OffscreenCanvasFrameDispatcher_h