Add support for switching the audio output device for HTMLMediaElements.

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index b63be0093bfe5f525cedbf2f74c220362f9df736..a30bfa0937893589a1b012f32c1cfc0b7fabf6d6 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -5,6 +5,8 @@
 #ifndef MEDIA_BASE_PIPELINE_H_
 #define MEDIA_BASE_PIPELINE_H_
 
+#include <string>
+
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ -21,6 +23,7 @@
 #include "media/base/text_track.h"
 #include "media/base/video_rotation.h"
 #include "ui/gfx/geometry/size.h"
+#include "url/gurl.h"
 
 namespace base {
 class SingleThreadTaskRunner;
@@ -163,6 +166,11 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   // channels proportionately for multi-channel audio streams.
   void SetVolume(float volume);
 
+  // Attempt to switch the audio output device.
+  void SwitchAudioOutputDevice(const std::string& device_id,
+                               const GURL& security_origin,
+                               const base::Callback<void(int)>& callback);
+
   // Returns the current media playback time, which progresses from 0 until
   // GetMediaDuration().
   base::TimeDelta GetMediaTime() const;
@@ -247,6 +255,12 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   // Carries out notifying filters that the volume has changed.
   void VolumeChangedTask(float volume);
 
+  // Carries out notifying filters that the audio output device has been
+  // switched.
+  void AudioOutputDeviceSwitchedTask(const std::string& device_id,
+                                     const GURL& security_origin,
+                                     const base::Callback<void(int)>& callback);
+
   // Carries out notifying filters that we are seeking to a new timestamp.
   void SeekTask(base::TimeDelta time, const PipelineStatusCB& seek_cb);