Revert r21117 as it caused reliability failures....

chrome/common/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/thread.h"
 #include "chrome/common/ipc_channel_proxy.h"
 #include "chrome/common/ipc_logging.h"
 #include "chrome/common/ipc_message_utils.h"
 
@@ skipping 254 matching lines @@
   filter->AddRef();
   context_->ipc_message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
       context_.get(), &Context::OnAddFilter, filter));
 }
 
 void ChannelProxy::RemoveFilter(MessageFilter* filter) {
   context_->ipc_message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
       context_.get(), &Context::OnRemoveFilter, filter));
 }
 
-void ChannelProxy::ClearIPCMessageLoop() {
-  context()->ClearIPCMessageLoop();
-}
-
 #if defined(OS_POSIX)
 // See the TODO regarding lazy initialization of the channel in
 // ChannelProxy::Init().
 // We assume that IPC::Channel::GetClientFileDescriptorMapping() is thread-safe.
 int ChannelProxy::GetClientFileDescriptor() const {
   Channel *channel = context_.get()->channel_;
   DCHECK(channel); // Channel must have been created first.
   return channel->GetClientFileDescriptor();
 }
 #endif
 
 //-----------------------------------------------------------------------------
 
 }  // namespace IPC