Looking up device id by session id for AudioRendererMixerInput

media/audio/audio_output_device.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.
 //
 // Audio rendering unit utilizing audio output stream provided by browser
 // process through IPC.
 //
 // Relationship of classes.
 //
 //  AudioOutputController                AudioOutputDevice
@@ skipping 91 matching lines @@
   void Stop() override;
   void Play() override;
   void Pause() override;
   bool SetVolume(double volume) override;
   OutputDeviceInfo GetOutputDeviceInfo() override;
 
   // Methods called on IO thread ----------------------------------------------
   // AudioOutputIPCDelegate methods.
   void OnStateChanged(AudioOutputIPCDelegateState state) override;
   void OnDeviceAuthorized(OutputDeviceStatus device_status,
-                          const media::AudioParameters& output_params) override;
+                          const media::AudioParameters& output_params,
+                          const std::string& matched_device_id) override;
   void OnStreamCreated(base::SharedMemoryHandle handle,
                        base::SyncSocket::Handle socket_handle,
                        int length) override;
   void OnIPCClosed() override;
 
  protected:
   // Magic required by ref_counted.h to avoid any code deleting the object
   // accidentally while there are references to it.
   friend class base::RefCountedThreadSafe<AudioOutputDevice>;
   ~AudioOutputDevice() override;
@@ skipping 45 matching lines @@
   bool play_on_start_;
 
   // The media session ID used to identify which input device to be started.
   // Only used by Unified IO.
   int session_id_;
 
   // ID of hardware output device to be used (provided session_id_ is zero)
   const std::string device_id_;
   const url::Origin security_origin_;
 
+  // If |device_id_| is empty and |session_id_| is not, |matched_device_id_| is
+  // received in OnDeviceAuthorized().
+  std::string matched_device_id_;
+
   // Our audio thread callback class.  See source file for details.
   class AudioThreadCallback;
 
   // In order to avoid a race between OnStreamCreated and Stop(), we use this
   // guard to control stopping and starting the audio thread.
   base::Lock audio_thread_lock_;
   AudioDeviceThread audio_thread_;
   scoped_ptr<AudioOutputDevice::AudioThreadCallback> audio_callback_;
 
   // Temporary hack to ignore OnStreamCreated() due to the user calling Stop()
   // so we don't start the audio thread pointing to a potentially freed
   // |callback_|.
   //
   // TODO(scherkus): Replace this by changing AudioRendererSink to either accept
   // the callback via Start(). See http://crbug.com/151051 for details.
   bool stopping_hack_;
 
   base::WaitableEvent did_receive_auth_;
   AudioParameters output_params_;
   OutputDeviceStatus device_status_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputDevice);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DEVICE_H_