Fix playback rate w/o audio. Remove unused SetPlaybackRate().

content/renderer/media/render_audiosourceprovider.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.
 //
 // RenderAudioSourceProvider provides a bridge between classes:
 //     WebKit::WebAudioSourceProvider <---> media::AudioRendererSink
 //
 // RenderAudioSourceProvider is a "sink" of audio, and uses a default
 // AudioOutputDevice if a client has not explicitly been set.
 //
@@ skipping 38 matching lines @@
   // If setClient() has been called, then WebKit calls provideInput()
   // periodically to get the rendered audio stream.
   virtual void provideInput(const WebKit::WebVector<float*>& audio_data,
                             size_t number_of_frames);
 
   // AudioRendererSink implementation.
   virtual void Start() OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual void Play() OVERRIDE;
   virtual void Pause(bool flush) OVERRIDE;
-  virtual void SetPlaybackRate(float rate) OVERRIDE;
   virtual bool SetVolume(double volume) OVERRIDE;
   virtual void Initialize(const media::AudioParameters& params,
                           RenderCallback* renderer) OVERRIDE;
 
  protected:
   virtual ~RenderAudioSourceProvider();
 
  private:
   // Set to true when Initialize() is called.
   bool is_initialized_;
   int channels_;
   int sample_rate_;
 
   bool is_running_;
   media::AudioRendererSink::RenderCallback* renderer_;
   WebKit::WebAudioSourceProviderClient* client_;
 
   // Protects access to sink_
   base::Lock sink_lock_;
 
   // default_sink_ is the default sink.
   scoped_refptr<media::AudioRendererSink> default_sink_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderAudioSourceProvider);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_RENDER_AUDIOSOURCEPROVIDER_H_