Merge AudioRendererImpl and AudioRendererBase; add NullAudioSink

media/base/audio_renderer_sink.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_SINK_H_
 #define MEDIA_BASE_AUDIO_RENDERER_SINK_H_
 
 #include <vector>
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
@@ skipping 10 matching lines @@
 class AudioRendererSink
     : public base::RefCountedThreadSafe<media::AudioRendererSink> {
  public:
   class RenderCallback {
    public:
     // Fills entire buffer of length |number_of_frames| but returns actual
     // number of frames it got from its source (|number_of_frames| in case of
     // continuous stream). That actual number of frames is passed to host
     // together with PCM audio data and host is free to use or ignore it.
     // TODO(crogers): use base:Callback instead.
-    virtual size_t Render(const std::vector<float*>& audio_data,
-                          size_t number_of_frames,
-                          size_t audio_delay_milliseconds) = 0;
+    virtual int Render(const std::vector<float*>& audio_data,
+                       int number_of_frames,
+                       int audio_delay_milliseconds) = 0;
 
     // Signals an error has occurred.
     virtual void OnRenderError() = 0;
 
    protected:
     virtual ~RenderCallback() {}
   };
 
   virtual ~AudioRendererSink() {}
 
   // Sets important information about the audio stream format.
   // It must be called before any of the other methods.
   virtual void Initialize(const AudioParameters& params,
                           RenderCallback* callback) = 0;
 
   // Starts audio playback.
   virtual void Start() = 0;
 
   // Stops audio playback.
   virtual void Stop() = 0;
 
   // Pauses playback.
   virtual void Pause(bool flush) = 0;
 
   // Resumes playback after calling Pause().
   virtual void Play() = 0;
 
+  // Called to inform the sink of a change in playback rate. Override if
+  // subclass needs the playback rate.
+  virtual void SetPlaybackRate(float rate) {};
+
   // Sets the playback volume, with range [0.0, 1.0] inclusive.
   // Returns |true| on success.
   virtual bool SetVolume(double volume) = 0;
 
   // Gets the playback volume, with range [0.0, 1.0] inclusive.
   virtual void GetVolume(double* volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_RENDERER_SINK_H_