Move IPC::MessageFilter and router to a separate file

ipc/ipc_forwarding_message_filter.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 "ipc/ipc_forwarding_message_filter.h"
 
 #include "base/bind.h"
 #include "base/location.h"
+#include "ipc/ipc_message.h"
 
 namespace IPC {
 
 ForwardingMessageFilter::ForwardingMessageFilter(
     const uint32* message_ids_to_filter,
     size_t num_message_ids_to_filter,
     base::TaskRunner* target_task_runner)
     : target_task_runner_(target_task_runner) {
   DCHECK(target_task_runner_.get());
   for (size_t i = 0; i < num_message_ids_to_filter; i++)
@@ skipping 28 matching lines @@
   }
 
   target_task_runner_->PostTask(FROM_HERE, base::Bind(handler, message));
   return true;
 }
 
 ForwardingMessageFilter::~ForwardingMessageFilter() {
 }
 
 }  // namespace IPC