Moving SwitchOutputDevice out of OutputDevice interface, eliminating OutputDevice

media/base/audio_renderer_sink.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_AUDIO_RENDERER_SINK_H_
 #define MEDIA_BASE_AUDIO_RENDERER_SINK_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 75 matching lines @@
 // Same as AudioRendererSink except that Initialize() and Start() can be called
 // again after Stop().
 // TODO(sandersd): Fold back into AudioRendererSink once all subclasses support
 // this.
 
 class RestartableAudioRendererSink : public AudioRendererSink {
  protected:
   ~RestartableAudioRendererSink() override {}
 };
 
+class SwitchableAudioRendererSink : public RestartableAudioRendererSink {
+ public:
+  // Attempts to switch the audio output device.
+  // Once the attempt is finished, |callback| is invoked with the
+  // result of the operation passed as a parameter. The result is a value from
+  // the media::OutputDeviceStatus enum.
+  // There is no guarantee about the thread where |callback| will
+  // be invoked, so users are advised to use media::BindToCurrentLoop() to
+  // ensure that |callback| runs on the correct thread.
+  // Note also that copy constructors and destructors for arguments bound to
+  // |callback| may run on arbitrary threads as |callback| is moved across
+  // threads. It is advisable to bind arguments such that they are released by
+  // |callback| when it runs in order to avoid surprises.
+  virtual void SwitchOutputDevice(const std::string& device_id,
+                                  const url::Origin& security_origin,
+                                  const OutputDeviceStatusCB& callback) = 0;
+
+ protected:
+  ~SwitchableAudioRendererSink() override {}
+};
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_RENDERER_SINK_H_