Reusing base::IdType<...> to implement SurfaceId.

content/renderer/render_frame_proxy.h

 // Copyright 2014 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_RENDERER_RENDER_FRAME_PROXY_H_
 #define CONTENT_RENDERER_RENDER_FRAME_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "cc/surfaces/surface_id.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/web/WebRemoteFrame.h"
 #include "third_party/WebKit/public/web/WebRemoteFrameClient.h"
 #include "url/origin.h"
 
 struct FrameMsg_BuffersSwapped_Params;
 struct FrameMsg_CompositorFrameSwapped_Params;
 
 namespace blink {
 class WebInputEvent;
 struct WebRect;
 }
 
 namespace cc {
-struct SurfaceId;
 struct SurfaceSequence;
 }
 
 namespace content {
 
 class ChildFrameCompositingHelper;
 class RenderFrameImpl;
 class RenderViewImpl;
 struct FrameReplicationState;
 
@@ skipping 136 matching lines @@
   scoped_refptr<ChildFrameCompositingHelper> compositing_helper_;
 
   RenderViewImpl* render_view_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameProxy);
 };
 
 }  // namespace
 
 #endif  // CONTENT_RENDERER_RENDER_FRAME_PROXY_H_