Let every "accelerated IO surface swapped" message have an identifier of the surface.

chrome/common/gpu_messages_internal.h

Index: chrome/common/gpu_messages_internal.h
diff --git a/chrome/common/gpu_messages_internal.h b/chrome/common/gpu_messages_internal.h
index 184d8f4249436fdef08601c8b4e7feddc4000268..0b8e3e6baf50f88c038da9b309f0ef82d9c6dc83 100644
--- a/chrome/common/gpu_messages_internal.h
+++ b/chrome/common/gpu_messages_internal.h
@@ -142,10 +142,11 @@ IPC_BEGIN_MESSAGES(GpuHost)
   // This message notifies the browser process that the renderer
   // swapped the buffers associated with the given "window", which
   // should cause the browser to redraw the compositor's contents.
-  IPC_MESSAGE_CONTROL3(GpuHostMsg_AcceleratedSurfaceBuffersSwapped,
+  IPC_MESSAGE_CONTROL4(GpuHostMsg_AcceleratedSurfaceBuffersSwapped,
                        int32, /* renderer_id */
                        int32, /* render_view_id */
-                       gfx::PluginWindowHandle /* window */)
+                       gfx::PluginWindowHandle /* window */,
+                       uint64 /* surface_id */)
 #endif
 
 IPC_END_MESSAGES(GpuHost)