Moving SwitchOutputDevice out of OutputDevice interface, eliminating OutputDevice

media/base/output_device.h

 // Copyright (c) 2015 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_OUTPUT_DEVICE_H_
 #define MEDIA_BASE_OUTPUT_DEVICE_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/media_export.h"
 #include "url/origin.h"
 
 namespace media {
 
 // Result of an audio output device switch operation
 enum OutputDeviceStatus {
   OUTPUT_DEVICE_STATUS_OK = 0,
   OUTPUT_DEVICE_STATUS_ERROR_NOT_FOUND,
   OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
   OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
   OUTPUT_DEVICE_STATUS_LAST = OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
 };
 
-typedef base::Callback<void(OutputDeviceStatus)> SwitchOutputDeviceCB;
+typedef base::Callback<void(OutputDeviceStatus)> OutputDeviceStatusCB;
 
 // OutputDevice is an interface that allows performing operations related
 // audio output devices.
 
 class OutputDevice {
  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::SwitchOutputDeviceResult 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 SwitchOutputDeviceCB& callback) = 0;
-
   // Returns the device's audio output parameters.
   // The return value is undefined if the device status (as returned by
   // GetDeviceStatus()) is different from OUTPUT_DEVICE_STATUS_OK.
   // If the parameters are not available, this method may block until they
   // become available.
   // This method must never be called on the IO thread.
   virtual AudioParameters GetOutputParameters() = 0;
 
   // Returns the status of output device.
   // If the status is not available, this method may block until it becomes
   // available. Must never be called on the IO thread.
   virtual OutputDeviceStatus GetDeviceStatus() = 0;
 
+  // Returns the device ID.
+  virtual std::string GetDeviceId() = 0;
+
  protected:
   virtual ~OutputDevice() {}
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_OUTPUT_DEVICE_H_