Add support for switching the audio output device for HTMLMediaElements.

media/base/audio_renderer_mixer_input.cc

Index: media/base/audio_renderer_mixer_input.cc
diff --git a/media/base/audio_renderer_mixer_input.cc b/media/base/audio_renderer_mixer_input.cc
index ab9f0a7ecab20e0d2c6ddae12fc6bcc690009960..20ad959c7ef764dfd5ba97fd1c9a748316436230 100644
--- a/media/base/audio_renderer_mixer_input.cc
+++ b/media/base/audio_renderer_mixer_input.cc
@@ -94,6 +94,16 @@ bool AudioRendererMixerInput::SetVolume(double volume) {
   return true;
 }
 
+void AudioRendererMixerInput::SwitchOutputDevice(
+    const std::string& device_id,
+    const GURL& security_origin,
+    const base::Callback<void(int)>& callback) {
+  DVLOG(1) << __FUNCTION__ << "(" << device_id << ", "
+           << security_origin << ")";
+  if (mixer_)
+    mixer_->SwitchOutputDevice(device_id, security_origin, callback);
+}
+
 double AudioRendererMixerInput::ProvideInput(AudioBus* audio_bus,
                                              base::TimeDelta buffer_delay) {
   int frames_filled = callback_->Render(