Send vsync timebase updates to the browser compositor

content/browser/gpu/gpu_process_host.h

Index: content/browser/gpu/gpu_process_host.h
diff --git a/content/browser/gpu/gpu_process_host.h b/content/browser/gpu/gpu_process_host.h
index 1ecd7d3541078cfecf1c2cf3d1cac8c6438d1d30..f99734be78ad099eae1eb7fdca2c5965bda77838 100644
--- a/content/browser/gpu/gpu_process_host.h
+++ b/content/browser/gpu/gpu_process_host.h
@@ -18,6 +18,7 @@
 #include "content/common/gpu/gpu_process_launch_causes.h"
 #include "content/public/browser/browser_child_process_host_delegate.h"
 #include "content/public/common/gpu_info.h"
+#include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_sender.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
@@ -77,6 +78,9 @@ class GpuProcessHost : public content::BrowserChildProcessHostDelegate,
   // IPC::Sender implementation.
   virtual bool Send(IPC::Message* msg) OVERRIDE;
 
+  // Adds a message filter to the GpuProcessHost's channel.
+  void AddFilter(IPC::ChannelProxy::MessageFilter* filter);
+
   // Tells the GPU process to create a new channel for communication with a
   // client. Once the GPU process responds asynchronously with the IPC handle
   // and GPUInfo, we call the callback.