Add support for switching the audio output device for HTMLMediaElements.

content/renderer/media/media_stream_audio_renderer.h

 // Copyright 2013 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_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_RENDERER_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_RENDERER_H_
 
+#include <string>
+
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
+#include "url/gurl.h"
 
 namespace content {
 
 class MediaStreamAudioRenderer
     : public base::RefCountedThreadSafe<MediaStreamAudioRenderer> {
  public:
   // Starts rendering audio.
   virtual void Start() = 0;
 
   // Stops rendering audio.
   virtual void Stop() = 0;
 
   // Resumes rendering audio after being paused.
   virtual void Play() = 0;
 
   // Temporarily suspends rendering audio. The audio stream might still be
   // active but new audio data is not provided to the consumer.
   virtual void Pause() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 
+  // Set the audio output device.
+  virtual void SwitchOutputDevice(
+      const std::string &device_id,
+      const GURL &security_origin,
+      const base::Callback<void(int)>& callback) = 0;
+
   // Time stamp that reflects the current render time. Should not be updated
   // when paused.
   virtual base::TimeDelta GetCurrentRenderTime() const = 0;
 
   // Returns true if the implementation is a local renderer and false
   // otherwise.
   virtual bool IsLocalRenderer() const = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<MediaStreamAudioRenderer>;
 
   MediaStreamAudioRenderer();
   virtual ~MediaStreamAudioRenderer();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaStreamAudioRenderer);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_RENDERER_H_