Implement WebGL's commit on the main thread

content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h

Index: content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h
diff --git a/content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h b/content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h
index c74ded0e54281007a3ffc0160a10f5df62c12209..9752e3b249ad2d7f17aede61303eee09714015c9 100644
--- a/content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h
+++ b/content/browser/renderer_host/offscreen_canvas_frame_receiver_impl.h
@@ -20,6 +20,8 @@ class OffscreenCanvasFrameReceiverImpl
 
   static void Create(blink::mojom::OffscreenCanvasFrameReceiverRequest request);
 
+  void SetClient(
+      blink::mojom::OffscreenCanvasFrameReceiverClientPtr client) override;
   void SubmitCompositorFrame(const cc::SurfaceId& surface_id,
                              cc::CompositorFrame frame) override;
 
@@ -32,6 +34,7 @@ class OffscreenCanvasFrameReceiverImpl
  private:
   cc::SurfaceId surface_id_;
   std::unique_ptr<cc::SurfaceFactory> surface_factory_;
+  blink::mojom::OffscreenCanvasFrameReceiverClientPtr client_;
 
   DISALLOW_COPY_AND_ASSIGN(OffscreenCanvasFrameReceiverImpl);
 };