Move IPC::MessageFilter and router to a separate file

ipc/ipc_forwarding_message_filter.h

 // 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.
 
 #ifndef IPC_IPC_FORWARDING_MESSAGE_FILTER_H_
 #define IPC_IPC_FORWARDING_MESSAGE_FILTER_H_
 
 #include <map>
 #include <set>
 
 #include "base/bind.h"
 #include "base/callback_forward.h"
 #include "base/synchronization/lock.h"
 #include "base/task_runner.h"
-#include "ipc/ipc_channel_proxy.h"
+#include "ipc/message_filter.h"
 
 namespace IPC {
 
 // This class can be used to intercept routed messages and
 // deliver them to a different task runner than they would otherwise
 // be sent. Messages are filtered based on type. To route these messages,
 // add a MessageRouter to the handler.
 //
 // The user of this class implements ForwardingMessageFilter::Client,
 // which will receive the intercepted messages, on the specified target thread.
-class IPC_EXPORT ForwardingMessageFilter : public ChannelProxy::MessageFilter {
+class IPC_EXPORT ForwardingMessageFilter : public MessageFilter {
  public:
 
   // The handler is invoked on the thread associated with
   // |target_task_runner| with messages that were intercepted by this filter.
   typedef base::Callback<void(const Message&)> Handler;
 
   // This filter will intercept |message_ids_to_filter| and post
   // them to the provided |target_task_runner|, where they will be given
   // to |handler|.
   //
   // The caller must ensure that |handler| outlives the lifetime of the filter.
   ForwardingMessageFilter(
       const uint32* message_ids_to_filter,
       size_t num_message_ids_to_filter,
       base::TaskRunner* target_task_runner);
 
   // Define the message routes to be filtered.
   void AddRoute(int routing_id, const Handler& handler);
   void RemoveRoute(int routing_id);
 
-  // ChannelProxy::MessageFilter methods:
+  // MessageFilter methods:
   virtual bool OnMessageReceived(const Message& message) OVERRIDE;
 
  private:
-  friend class ChannelProxy::MessageFilter;
   virtual ~ForwardingMessageFilter();
 
   std::set<int> message_ids_to_filter_;
 
   // The handler_ only gets Run on the thread corresponding to
   // target_task_runner_.
   scoped_refptr<base::TaskRunner> target_task_runner_;
 
   // Protects access to routes_.
   base::Lock handlers_lock_;
 
   // Indicates the routing_ids for which messages should be filtered.
   std::map<int, Handler> handlers_;
 
   DISALLOW_COPY_AND_ASSIGN(ForwardingMessageFilter);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_FORWARDING_MESSAGE_FILTER_H_