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

chrome/common/render_messages_internal.h

 // Copyright (c) 2010 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.
 
 // This header is meant to be included in multiple passes, hence no traditional
 // header guard.
 // See ipc_message_macros.h for explanation of the macros and passes.
 
 #include <map>
 #include <string>
@@ skipping 2220 matching lines @@
   // plug-in to indicate that a new backing store was allocated for that
   // plug-in instance.
   //
   // NOTE: the original intent was to pass a mach port as the IOSurface
   // identifier but it looks like that will be a lot of work. For now we pass an
   // ID from IOSurfaceGetID.
   IPC_MESSAGE_ROUTED4(ViewHostMsg_AcceleratedSurfaceSetIOSurface,
                       gfx::PluginWindowHandle /* window */,
                       int32 /* width */,
                       int32 /* height */,
-                      uint64 /* identifier for IOSurface */)
+                      uint64 /* surface_id */)
 
   // This message notifies the browser process that the plug-in
   // swapped the buffers associated with the given "window", which
   // should cause the browser to redraw the various plug-ins'
   // contents.
-  IPC_MESSAGE_ROUTED1(ViewHostMsg_AcceleratedSurfaceBuffersSwapped,
-                      gfx::PluginWindowHandle /* window */)
+  IPC_MESSAGE_ROUTED2(ViewHostMsg_AcceleratedSurfaceBuffersSwapped,
+                      gfx::PluginWindowHandle /* window */,
+                      uint64 /* surface_id */)
 #endif
 
   // A renderer sends this to the browser process when it wants to create a
   // worker.  The browser will create the worker process if necessary, and
   // will return the route id on success.  On error returns MSG_ROUTING_NONE.
   IPC_SYNC_MESSAGE_CONTROL1_1(ViewHostMsg_CreateWorker,
                               ViewHostMsg_CreateWorker_Params,
                               int /* route_id */)
 
   // This message is sent to the browser to see if an instance of this shared
@@ skipping 797 matching lines @@
                               base::PlatformFileInfo, /* info */
                               base::PlatformFileError /* error_code */)
 
   // Get the directory's contents.
   IPC_SYNC_MESSAGE_CONTROL1_2(ViewHostMsg_PepperGetDirContents,
                               FilePath /* path */,
                               PepperDirContents, /* contents */
                               base::PlatformFileError /* error_code */)
 
 IPC_END_MESSAGES(ViewHost)