Reland of Add groupid for media devices. Group audio devices.

media/audio/audio_manager.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_AUDIO_AUDIO_MANAGER_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 223 matching lines @@
   // Returns the device id of an output device that belongs to the same hardware
   // as the specified input device.
   // If the hardware has only an input device (e.g. a webcam), the return value
   // will be empty (which the caller can then interpret to be the default output
   // device).  Implementations that don't yet support this feature, must return
   // an empty string. Must be called on the audio worker thread (see
   // GetWorkerTaskRunner()).
   virtual std::string GetAssociatedOutputDeviceID(
       const std::string& input_device_id) = 0;
 
+  // These functions assign group ids to devices based on their device ids.
+  // The default implementation is an attempt to do this based on
+  // GetAssociatedOutputDeviceID. Must be called on the audio worker thread
+  // (see GetWorkerTaskRunner()).

[Guido Urdaneta, 2016/09/05 13:15:53]

Actually, the comment should say GetTaskRunner() instead of
GetWorkerTaskRunner().
Feel free to fix other instances if this as a drive-by.

[Max Morin, 2016/09/05 13:53:56]

Done.

+  virtual std::string GetGroupIDOutput(const std::string& output_device_id) = 0;
+  virtual std::string GetGroupIDInput(const std::string& input_device_id) = 0;
+
   // Create a new AudioLog object for tracking the behavior for one or more
   // instances of the given component.  See AudioLogFactory for more details.
   virtual std::unique_ptr<AudioLog> CreateAudioLog(
       AudioLogFactory::AudioComponent component) = 0;
 
  protected:
   AudioManager(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner);
   virtual ~AudioManager();
 
  private:
   friend class base::DeleteHelper<AudioManager>;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner_;
   DISALLOW_COPY_AND_ASSIGN(AudioManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_H_