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

content/browser/gpu/gpu_process_host_ui_shim.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_GPU_GPU_PROCESS_HOST_UI_SHIM_H_
 #define CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_UI_SHIM_H_
 
 // This class lives on the UI thread and supports classes like the
 // BackingStoreProxy, which must live on the UI thread. The IO thread
 // portion of this class, the GpuProcessHost, is responsible for
@@ skipping 60 matching lines @@
   // IPC::Listener implementation.
   // The GpuProcessHost causes this to be called on the UI thread to
   // dispatch the incoming messages from the GPU process, which are
   // actually received on the IO thread.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   CONTENT_EXPORT void SimulateRemoveAllContext();
   CONTENT_EXPORT void SimulateCrash();
   CONTENT_EXPORT void SimulateHang();
 
+#if defined(TOOLKIT_GTK)
+  CONTENT_EXPORT void AcceleratedCompositingStateChange(
+      int32 surface_id, bool compositing_active);
+#endif
+
  private:
   explicit GpuProcessHostUIShim(int host_id);
   virtual ~GpuProcessHostUIShim();
 
   // Message handlers.
   bool OnControlMessageReceived(const IPC::Message& message);
 
   void OnLogMessage(int level, const std::string& header,
       const std::string& message);
 #if defined(TOOLKIT_GTK) || defined(OS_WIN)
@@ skipping 18 matching lines @@
                                base::TimeDelta interval);
   void OnFrameDrawn(const ui::LatencyInfo& latency_info);
 
   // The serial number of the GpuProcessHost / GpuProcessHostUIShim pair.
   int host_id_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_UI_SHIM_H_