(not for review) Fix composited-to-non-composited corruption on Linux.

content/common/gpu/gpu_messages.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.
 
 // Multiply-included message file, hence no include guard here, but see below
 // for a much smaller-than-usual include guard section.
 
 #include <string>
 #include <vector>
 
@@ skipping 287 matching lines @@
 
 // Tells the GPU process to crash.
 IPC_MESSAGE_CONTROL0(GpuMsg_Crash)
 
 // Tells the GPU process to hang.
 IPC_MESSAGE_CONTROL0(GpuMsg_Hang)
 
 // Tells the GPU process to disable the watchdog thread.
 IPC_MESSAGE_CONTROL0(GpuMsg_DisableWatchdog)
 
+#if defined(TOOLKIT_GTK)
+// Tells the GPU process that a surface has enabled or disabled compositing.
+IPC_MESSAGE_CONTROL2(GpuMsg_AcceleratedCompositingStateChange,
+                     int32 , /* surface_id */
+                     bool /* compositing_active */)
+#endif
+
 //------------------------------------------------------------------------------
 // GPU Host Messages
 // These are messages to the browser.
 
 // A renderer sends this when it wants to create a connection to the GPU
 // process. The browser will create the GPU process if necessary, and will
 // return a handle to the channel via a GpuChannelEstablished message.
 IPC_SYNC_MESSAGE_CONTROL1_3(GpuHostMsg_EstablishGpuChannel,
                             content::CauseForGpuLaunch,
                             int /* client id */,
@@ skipping 487 matching lines @@
                     gfx::Size /* buffer_size */,
                     gfx::Rect /* visible_rect */)
 
 // Report successful copy of a capture of a surface.
 IPC_MESSAGE_ROUTED1(SurfaceCapturerHostMsg_NotifyCopyCaptureDone,
                     int32 /* frame_id */)
 
 // Report error.
 IPC_MESSAGE_ROUTED1(SurfaceCapturerHostMsg_NotifyError,
                     content::SurfaceCapturer::Error /* error */)