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

third_party/WebKit/Source/platform/graphics/CanvasSurfaceLayerBridge.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 CanvasSurfaceLayerBridge_h
 #define CanvasSurfaceLayerBridge_h
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_reference_factory.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "platform/PlatformExport.h"
 #include "public/platform/modules/offscreencanvas/offscreen_canvas_surface.mojom-blink.h"
 #include <memory>
 
 namespace cc {
 class Layer;
 class SurfaceInfo;
 }  // namespace cc
 
 namespace blink {
 
 class WebLayer;
+class WebLayerTreeView;
 
 class PLATFORM_EXPORT CanvasSurfaceLayerBridgeObserver {
  public:
   CanvasSurfaceLayerBridgeObserver() {}
   virtual ~CanvasSurfaceLayerBridgeObserver() {}
 
   virtual void OnWebLayerReplaced() = 0;
 };
 
 class PLATFORM_EXPORT CanvasSurfaceLayerBridge
     : NON_EXPORTED_BASE(public mojom::blink::OffscreenCanvasSurfaceClient) {
  public:
-  explicit CanvasSurfaceLayerBridge(CanvasSurfaceLayerBridgeObserver*);
+  explicit CanvasSurfaceLayerBridge(CanvasSurfaceLayerBridgeObserver*,
+                                    WebLayerTreeView*);
   ~CanvasSurfaceLayerBridge();
   void createSolidColorLayer();
   WebLayer* getWebLayer() const { return m_webLayer.get(); }
   const cc::FrameSinkId& getFrameSinkId() const { return m_frameSinkId; }
 
   // Implementation of mojom::blink::OffscreenCanvasSurfaceClient
   void OnSurfaceCreated(const cc::SurfaceInfo&) override;
 
   void satisfyCallback(const cc::SurfaceSequence&);
   void requireCallback(const cc::SurfaceId&, const cc::SurfaceSequence&);
 
  private:
   scoped_refptr<cc::Layer> m_CCLayer;
   std::unique_ptr<WebLayer> m_webLayer;
 
   scoped_refptr<cc::SurfaceReferenceFactory> m_refFactory;
   base::WeakPtrFactory<CanvasSurfaceLayerBridge> m_weakFactory;
 
   CanvasSurfaceLayerBridgeObserver* m_observer;
 
   mojom::blink::OffscreenCanvasSurfacePtr m_service;
   mojo::Binding<mojom::blink::OffscreenCanvasSurfaceClient> m_binding;
 
-  cc::FrameSinkId m_frameSinkId;
+  const cc::FrameSinkId m_frameSinkId;
   cc::SurfaceId m_currentSurfaceId;
+  const cc::FrameSinkId m_parentFrameSinkId;
 };
 
 }  // namespace blink
 
 #endif  // CanvasSurfaceLayerBridge_h