Merge the IPCs used for GPU process synchronization.

content/common/gpu/gpu_messages.h

Index: content/common/gpu/gpu_messages.h
diff --git a/content/common/gpu/gpu_messages.h b/content/common/gpu/gpu_messages.h
index e8db3a9a8ea05ab46f001dc9db692d99f70ac103..f50d46e066a4e585ff0238e2c9f36d983e23ddd0 100644
--- a/content/common/gpu/gpu_messages.h
+++ b/content/common/gpu/gpu_messages.h
@@ -201,13 +201,9 @@ IPC_MESSAGE_ROUTED2(AcceleratedSurfaceMsg_NewACK,
                     uint64 /* surface_handle */,
                     TransportDIB::Handle /* shared memory buffer */)
 
-// Tells the GPU process that the browser process handled the swap
-// buffers request.
-IPC_MESSAGE_ROUTED0(AcceleratedSurfaceMsg_BuffersSwappedACK)
-
-// Tells the GPU process that the browser process handled the
-// PostSubBuffer command.
-IPC_MESSAGE_ROUTED0(AcceleratedSurfaceMsg_PostSubBufferACK)
+// Tells the GPU process that the browser process has handled the swap
+// buffers or post sub-buffer request.
+IPC_MESSAGE_ROUTED0(AcceleratedSurfaceMsg_BufferPresented)
 
 // Tells the GPU process to remove all contexts.
 IPC_MESSAGE_CONTROL0(GpuMsg_Clean)