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 105 matching lines @@
   // ideally must not be called from the UI thread or other time sensitive
   // threads to avoid blocking the rest of the application.
   virtual void ShowAudioInputSettings() = 0;
 
   // Appends a list of available input devices to |device_names|,
   // which must initially be empty. It is not guaranteed that all the
   // devices in the list support all formats and sample rates for
   // recording.
   //
   // Not threadsafe; in production this should only be called from the
-  // Audio worker thread (see GetWorkerTaskRunner()).
+  // Audio worker thread (see GetTaskRunner()).
   virtual void GetAudioInputDeviceNames(AudioDeviceNames* device_names) = 0;
 
   // Appends a list of available output devices to |device_names|,
   // which must initially be empty.
   //
   // Not threadsafe; in production this should only be called from the
-  // Audio worker thread (see GetWorkerTaskRunner()).
+  // Audio worker thread (see GetTaskRunner()).
   virtual void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) = 0;
 
   // Log callback used for sending log messages from a stream to the object
   // that manages the stream.
   using LogCallback = base::Callback<void(const std::string&)>;
 
   // Factory for all the supported stream formats. |params| defines parameters
   // of the audio stream to be created.
   //
   // |params.sample_per_packet| is the requested buffer allocation which the
@@ skipping 86 matching lines @@
   // version of this interface.
   virtual AudioParameters GetInputStreamParameters(
       const std::string& device_id) = 0;
 
   // 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()).
+  // GetTaskRunner()).
   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 GetTaskRunner()).
+  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_