Allow cmdbuffer creation from compositor thread.

content/renderer/gpu/command_buffer_proxy.cc

 // Copyright (c) 2011 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.
 
 #include "content/renderer/gpu/command_buffer_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/process_util.h"
 #include "base/shared_memory.h"
@@ skipping 22 matching lines @@
   // in this process.
   for (TransferBufferMap::iterator it = transfer_buffers_.begin();
        it != transfer_buffers_.end();
        ++it) {
     delete it->second.shared_memory;
     it->second.shared_memory = NULL;
   }
 }
 
 bool CommandBufferProxy::OnMessageReceived(const IPC::Message& message) {
+  if (IsOrphaned())

[nduca, 2011/08/15 22:28:36]

How about doing this in the MessageFilter side before calling OnMessageRecieved
on the listener? That would reduce fragility...

+    return false;
+
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(CommandBufferProxy, message)
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_UpdateState, OnUpdateState);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_Destroyed, OnDestroyed);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_SwapBuffers, OnSwapBuffers);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_NotifyRepaint,
                         OnNotifyRepaint);
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ skipping 383 matching lines @@
   delete msg;
   return false;
 }
 
 void CommandBufferProxy::OnUpdateState(const gpu::CommandBuffer::State& state) {
   // Handle wraparound. It works as long as we don't have more than 2B state
   // updates in flight across which reordering occurs.
   if (state.generation - last_state_.generation < 0x80000000U)
     last_state_ = state;
 }