Use observer pattern instead of sniffing SwapCompositorFrame IPC

content/browser/web_contents/web_contents_impl.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <stdint.h>
 
 #include <functional>
@@ skipping 660 matching lines @@
   void LostMouseLock(RenderWidgetHostImpl* render_widget_host) override;
   bool HasMouseLock(RenderWidgetHostImpl* render_widget_host) override;
   RenderWidgetHostImpl* GetMouseLockWidget() override;
   void OnRenderFrameProxyVisibilityChanged(bool visible) override;
   void SendScreenRects() override;
   TextInputManager* GetTextInputManager() override;
   bool OnUpdateDragCursor() override;
   bool IsWidgetForMainFrame(RenderWidgetHostImpl* render_widget_host) override;
   bool AddDomainInfoToRapporSample(rappor::Sample* sample) override;
   void FocusedNodeTouched(bool editable) override;
+  void DidReceiveCompositorFrame() override;
 
   // RenderFrameHostManager::Delegate ------------------------------------------
 
   bool CreateRenderViewForRenderManager(
       RenderViewHost* render_view_host,
       int opener_frame_routing_id,
       int proxy_routing_id,
       const FrameReplicationState& replicated_frame_state) override;
   void CreateRenderWidgetHostViewForRenderManager(
       RenderViewHost* render_view_host) override;
@@ skipping 865 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendWrapper);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_