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

content/browser/gpu/gpu_process_host_ui_shim.h

Index: content/browser/gpu/gpu_process_host_ui_shim.h
diff --git a/content/browser/gpu/gpu_process_host_ui_shim.h b/content/browser/gpu/gpu_process_host_ui_shim.h
index 9f4329a10a5898418a502e13b544af7fe572e8cb..256904c89ddf5d76f35427ee9e60eb637bb47bae 100644
--- a/content/browser/gpu/gpu_process_host_ui_shim.h
+++ b/content/browser/gpu/gpu_process_host_ui_shim.h
@@ -78,6 +78,11 @@ class GpuProcessHostUIShim : public IPC::Listener,
   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();