thread.h is not needed by ipc_channel_proxy.cc.

ipc/ipc_channel_proxy.cc

 // Copyright (c) 2006-2008 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 "base/message_loop.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
-#include "base/threading/thread.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_logging.h"
 #include "ipc/ipc_message_utils.h"
 
 namespace IPC {
 
 //------------------------------------------------------------------------------
 
 // This task ensures the message is deleted if the task is deleted without
 // having been run.
@@ skipping 355 matching lines @@
   Channel *channel = context_.get()->channel_.get();
   // Channel must have been created first.
   DCHECK(channel) << context_.get()->channel_id_;
   return channel->GetClientFileDescriptor();
 }
 #endif
 
 //-----------------------------------------------------------------------------
 
 }  // namespace IPC