Add support for switching the audio output device for HTMLMediaElements.

media/base/audio_renderer.h

Index: media/base/audio_renderer.h
diff --git a/media/base/audio_renderer.h b/media/base/audio_renderer.h
index 586936a1e81bc4e5f94da23ffc12bd2f6904e514..c74b7e46f0121a34d048bc10c5be5fe8bda728d4 100644
--- a/media/base/audio_renderer.h
+++ b/media/base/audio_renderer.h
@@ -5,12 +5,15 @@
 #ifndef MEDIA_BASE_AUDIO_RENDERER_H_
 #define MEDIA_BASE_AUDIO_RENDERER_H_
 
+#include <string>
+
 #include "base/callback.h"
 #include "base/time/time.h"
 #include "media/base/buffering_state.h"
 #include "media/base/decryptor.h"
 #include "media/base/media_export.h"
 #include "media/base/pipeline_status.h"
+#include "url/gurl.h"
 
 namespace media {
 
@@ -69,6 +72,12 @@ class MEDIA_EXPORT AudioRenderer {
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 
+  // Switches the output device.

[miu, 2015/06/03 21:01:01]

Please do the same here as I suggested in AudioRendererSink (re: documentation,
naming the type of the callback, and using an enum).

+  virtual void SwitchOutputDevice(
+      const std::string& device_id,
+      const GURL& security_origin,
+      const base::Callback<void(int)>& callback) = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioRenderer);
 };