Add support for switching the audio output device for HTMLMediaElements.

content/renderer/media/media_stream_audio_renderer.h

Index: content/renderer/media/media_stream_audio_renderer.h
diff --git a/content/renderer/media/media_stream_audio_renderer.h b/content/renderer/media/media_stream_audio_renderer.h
index 41e32239115c3aae8cb9f43f034cbb06d6969979..7a99b59727f8f1ad2639c1540200575c28315fa4 100644
--- a/content/renderer/media/media_stream_audio_renderer.h
+++ b/content/renderer/media/media_stream_audio_renderer.h
@@ -5,8 +5,12 @@
 #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 {
 
@@ -29,6 +33,12 @@ class MediaStreamAudioRenderer
   // 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;