Let IPC::SyncMessageFilter take advantage of thread-safe Send.

content/common/gpu/client/gpu_channel_host.cc

 // Copyright (c) 2012 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/common/gpu/client/gpu_channel_host.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 60 matching lines @@
                              base::WaitableEvent* shutdown_event) {
   DCHECK(factory_->IsMainThread());
   // Open a channel to the GPU process. We pass NULL as the main listener here
   // since we need to filter everything to route it to the right thread.
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner =
       factory_->GetIOThreadTaskRunner();
   channel_ = IPC::SyncChannel::Create(
       channel_handle, IPC::Channel::MODE_CLIENT, NULL, io_task_runner.get(),
       true, shutdown_event, factory_->GetAttachmentBroker());
 
-  sync_filter_ = new IPC::SyncMessageFilter(shutdown_event);
-
-  channel_->AddFilter(sync_filter_.get());
+  sync_filter_ = channel_->CreateSyncMessageFilter();
 
   channel_filter_ = new MessageFilter();
 
   // Install the filter last, because we intercept all leftover
   // messages.
   channel_->AddFilter(channel_filter_.get());
 }
 
 bool GpuChannelHost::Send(IPC::Message* msg) {
   // Callee takes ownership of message, regardless of whether Send is
@@ skipping 339 matching lines @@
 
   listeners_.clear();
 }
 
 bool GpuChannelHost::MessageFilter::IsLost() const {
   AutoLock lock(lock_);
   return lost_;
 }
 
 }  // namespace content