Decouple IPC::MessageFilter from IPC::Channel

ipc/ipc_sync_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_SYNC_MESSAGE_FILTER_H_
 #define IPC_IPC_SYNC_MESSAGE_FILTER_H_
 
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 16 matching lines @@
 // receiving messages while waiting for a response.  Note that this object can
 // be used to send simultaneous synchronous messages from different threads.
 class IPC_EXPORT SyncMessageFilter : public MessageFilter, public Sender {
  public:
   explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
 
   // MessageSender implementation.
   virtual bool Send(Message* message) OVERRIDE;
 
   // MessageFilter implementation.
-  virtual void OnFilterAdded(Channel* channel) OVERRIDE;
-  virtual void OnChannelError() OVERRIDE;
-  virtual void OnChannelClosing() OVERRIDE;
+  virtual void OnFilterAdded(Sender* sender) OVERRIDE;
+  virtual void OnSenderError() OVERRIDE;
+  virtual void OnSenderClosing() OVERRIDE;
   virtual bool OnMessageReceived(const Message& message) OVERRIDE;
 
  protected:
   virtual ~SyncMessageFilter();
 
  private:
   void SendOnIOThread(Message* message);
   // Signal all the pending sends as done, used in an error condition.
   void SignalAllEvents();
 
   // The channel to which this filter was added.
-  Channel* channel_;
+  Sender* sender_;
 
   // The process's main thread.
   scoped_refptr<base::MessageLoopProxy> listener_loop_;
 
   // The message loop where the Channel lives.
   scoped_refptr<base::MessageLoopProxy> io_loop_;
 
   typedef std::set<PendingSyncMsg*> PendingSyncMessages;
   PendingSyncMessages pending_sync_messages_;
 
   // Locks data members above.
   base::Lock lock_;
 
   base::WaitableEvent* shutdown_event_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_SYNC_MESSAGE_FILTER_H_