Make IPC::Channel::Listener:OnMessageReceived have a return value indicating ...

chrome/renderer/command_buffer_proxy.cc

Index: chrome/renderer/command_buffer_proxy.cc
===================================================================
--- chrome/renderer/command_buffer_proxy.cc	(revision 70108)
+++ chrome/renderer/command_buffer_proxy.cc	(working copy)
@@ -34,14 +34,17 @@
   }
 }
 
-void CommandBufferProxy::OnMessageReceived(const IPC::Message& message) {
+bool CommandBufferProxy::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(CommandBufferProxy, message)
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_UpdateState, OnUpdateState);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_SwapBuffers, OnSwapBuffers);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_NotifyRepaint,
                         OnNotifyRepaint);
-    IPC_MESSAGE_UNHANDLED_ERROR()
+    IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
+  DCHECK(handled);
+  return handled;
 }
 
 void CommandBufferProxy::OnChannelError() {