Add support for switching the audio output device for HTMLMediaElements.

media/base/audio_renderer_mixer_input.h

Index: media/base/audio_renderer_mixer_input.h
diff --git a/media/base/audio_renderer_mixer_input.h b/media/base/audio_renderer_mixer_input.h
index d097aa874ad86e5d0c0847a2ce5ff957ba49308b..58c71da8fa4092236ca207efb3855c1944f90425 100644
--- a/media/base/audio_renderer_mixer_input.h
+++ b/media/base/audio_renderer_mixer_input.h
@@ -5,11 +5,13 @@
 #ifndef MEDIA_BASE_AUDIO_RENDERER_MIXER_INPUT_H_
 #define MEDIA_BASE_AUDIO_RENDERER_MIXER_INPUT_H_
 
+#include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "media/base/audio_converter.h"
 #include "media/base/audio_renderer_sink.h"
+#include "url/gurl.h"
 
 namespace media {
 
@@ -32,6 +34,9 @@ class MEDIA_EXPORT AudioRendererMixerInput
   void Play() override;
   void Pause() override;
   bool SetVolume(double volume) override;
+  void SwitchOutputDevice(const std::string& device_id,
+                          const GURL& security_origin,
+                          const base::Callback<void(int)>& callback) override;
   void Initialize(const AudioParameters& params,
                   AudioRendererSink::RenderCallback* renderer) override;