Implement WebGL's commit on the main thread

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/surfaces/surface_id.h"
+#include "mojo/public/cpp/bindings/binding.h"
 #include "platform/graphics/OffscreenCanvasFrameDispatcher.h"
+#include "platform/graphics/StaticBitmapImage.h"
 #include "public/platform/modules/offscreencanvas/offscreen_canvas_surface.mojom-blink.h"
 #include <memory>
 
 namespace blink {
 
-class PLATFORM_EXPORT OffscreenCanvasFrameDispatcherImpl final : public OffscreenCanvasFrameDispatcher {
+class PLATFORM_EXPORT OffscreenCanvasFrameDispatcherImpl final : public OffscreenCanvasFrameDispatcher, public mojom::blink::OffscreenCanvasFrameReceiverClient {
 public:
     explicit OffscreenCanvasFrameDispatcherImpl(uint32_t clientId, uint32_t localId, uint64_t nonce, int width, int height);
 
     // OffscreenCanvasFrameDispatcher implementation.
     ~OffscreenCanvasFrameDispatcherImpl() override {}
-    void dispatchFrame() override;
+    void dispatchFrame(RefPtr<StaticBitmapImage>) override;
+
+    // OffscreenCanvasFrameReceiverClient implementation.
+    void ReturnResources(Vector<cc::mojom::blink::ReturnedResourcePtr> resources) override;

[xlai (Olivia), 2016/09/14 17:54:46]

Hmmm..Is resourceId the only and single item that will be used throughout the
whole implementation? Otherwise, can you use the ReturnResource typemap instead
of using the Mojom type directly? It's similar to the way
compositor_frame.typemap is brought to Blink. 

 
 private:
     const cc::SurfaceId m_surfaceId;
     const int m_width;
     const int m_height;
     mojom::blink::OffscreenCanvasFrameReceiverPtr m_service;
+
+    HashMap<unsigned, RefPtr<StaticBitmapImage>> m_cachedImages;
+    mojo::Binding<mojom::blink::OffscreenCanvasFrameReceiverClient> m_binding;
 };
 
 } // namespace blink
 
 #endif // OffscreenCanvasFrameDispatcherImpl_h