Add support for switching the audio output device for HTMLMediaElements.

media/blink/webaudiosourceprovider_impl.h

Index: media/blink/webaudiosourceprovider_impl.h
diff --git a/media/blink/webaudiosourceprovider_impl.h b/media/blink/webaudiosourceprovider_impl.h
index 77204b2215ca6916b7b3784b53d3364150ba6aa4..65e8aa2ed4b00a4e66dc587577c2e9ce6f616b76 100644
--- a/media/blink/webaudiosourceprovider_impl.h
+++ b/media/blink/webaudiosourceprovider_impl.h
@@ -5,6 +5,8 @@
 #ifndef MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 #define MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 
+#include <string>
+
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
@@ -46,6 +48,9 @@ class MEDIA_EXPORT WebAudioSourceProviderImpl
   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,
                   RenderCallback* renderer) override;