Revert r180578, r180591, and r180604 from 1410 branch.

media/base/audio_renderer.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 MEDIA_BASE_AUDIO_RENDERER_H_
 #define MEDIA_BASE_AUDIO_RENDERER_H_
 
 #include <list>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
 #include "media/base/media_export.h"
 #include "media/base/pipeline_status.h"
 
 namespace media {
 
 class AudioDecoder;
 class DemuxerStream;
 
-class MEDIA_EXPORT AudioRenderer {
+class MEDIA_EXPORT AudioRenderer
+    : public base::RefCountedThreadSafe<AudioRenderer> {
  public:
   typedef std::list<scoped_refptr<AudioDecoder> > AudioDecoderList;
 
   // First parameter is the current time that has been rendered.
   // Second parameter is the maximum time value that the clock cannot exceed.
   typedef base::Callback<void(base::TimeDelta, base::TimeDelta)> TimeCB;
 
-  AudioRenderer();
-  virtual ~AudioRenderer();
-
   // Initialize a AudioRenderer with the given AudioDecoder, executing the
   // |init_cb| upon completion.
   //
   // |statistics_cb| is executed periodically with audio rendering stats.
   //
   // |underflow_cb| is executed when the renderer runs out of data to pass to
   // the audio card during playback. ResumeAfterUnderflow() must be called
   // to resume playback. Pause(), Preroll(), or Stop() cancels the underflow
   // condition.
   //
@@ skipping 43 matching lines @@
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 
   // Resumes playback after underflow occurs.
   //
   // |buffer_more_audio| is set to true if you want to increase the size of the
   // decoded audio buffer.
   virtual void ResumeAfterUnderflow(bool buffer_more_audio) = 0;
 
+ protected:
+  friend class base::RefCountedThreadSafe<AudioRenderer>;
+
+  AudioRenderer();
+  virtual ~AudioRenderer();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioRenderer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_RENDERER_H_