Decouple IPC::MessageFilter from IPC::Channel

content/child/child_histogram_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 CONTENT_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
 #define CONTENT_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ipc/message_filter.h"
 
 namespace base {
 class HistogramDeltaSerialization;
 class MessageLoopProxy;
 }  // namespace base
 
 namespace content {
 
 class ChildHistogramMessageFilter : public IPC::MessageFilter {
  public:
   ChildHistogramMessageFilter();
 
   // IPC::MessageFilter implementation.
-  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
+  virtual void OnFilterAdded(IPC::Sender* sender) OVERRIDE;
   virtual void OnFilterRemoved() OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   void SendHistograms(int sequence_number);
 
  private:
   typedef std::vector<std::string> HistogramPickledList;
 
   virtual ~ChildHistogramMessageFilter();
 
   // Message handlers.
   virtual void OnGetChildHistogramData(int sequence_number);
 
   // Extract snapshot data and then send it off the the Browser process.
   // Send only a delta to what we have already sent.
   void UploadAllHistograms(int sequence_number);
 
-  IPC::Channel* channel_;
+  IPC::Sender* sender_;
 
   scoped_refptr<base::MessageLoopProxy> io_message_loop_;
 
   // Prepares histogram deltas for transmission.
   scoped_ptr<base::HistogramDeltaSerialization> histogram_delta_serialization_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildHistogramMessageFilter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_HISTOGRAM_MESSAGE_FILTER_H_