Wire up the output device id and provide an implementation on Windows.

media/audio/audio_output_controller.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_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/atomic_ref_count.h"
 #include "base/callback.h"
 #include "base/cancelable_callback.h"
@@ skipping 82 matching lines @@
     virtual int Read(bool block, const AudioBus* source, AudioBus* dest) = 0;
 
     // Close this synchronous reader.
     virtual void Close() = 0;
   };
 
   // Factory method for creating an AudioOutputController.
   // This also creates and opens an AudioOutputStream on the audio manager
   // thread, and if this is successful, the |event_handler| will receive an
   // OnCreated() call from the same audio manager thread.  |audio_manager| must
   // outlive AudioOutputController.

[henrika (OOO until Aug 14), 2013/09/06 08:44:38]

Should we extend the comment and mention device IDs as well?

[tommi (sloooow) - chröme, 2013/09/06 11:01:35]

Done.

   static scoped_refptr<AudioOutputController> Create(
       AudioManager* audio_manager, EventHandler* event_handler,
-      const AudioParameters& params, const std::string& input_device_id,
-      SyncReader* sync_reader);
+      const AudioParameters& params, const std::string& output_device_id,
+      const std::string& input_device_id, SyncReader* sync_reader);
 
   // Methods to control playback of the stream.
 
   // Starts the playback of this audio output stream.
   void Play();
 
   // Pause this audio output stream.
   void Pause();
 
   // Closes the audio output stream. The state is changed and the resources
@@ skipping 41 matching lines @@
   friend class base::RefCountedThreadSafe<AudioOutputController>;
   virtual ~AudioOutputController();
 
  private:
   // We are polling sync reader if data became available.
   static const int kPollNumAttempts;
   static const int kPollPauseInMilliseconds;
 
   AudioOutputController(AudioManager* audio_manager, EventHandler* handler,
                         const AudioParameters& params,
+                        const std::string& output_device_id,
                         const std::string& input_device_id,
                         SyncReader* sync_reader);
 
   // The following methods are executed on the audio manager thread.
   void DoCreate(bool is_for_device_change);
   void DoPlay();
   void DoPause();
   void DoClose();
   void DoSetVolume(double volume);
   void DoReportError();
@@ skipping 12 matching lines @@
 
   // Sanity-check that entry/exit to OnMoreIOData() by the hardware audio thread
   // happens only between AudioOutputStream::Start() and Stop().
   void AllowEntryToOnMoreIOData();
   void DisallowEntryToOnMoreIOData();
 
   AudioManager* const audio_manager_;
   const AudioParameters params_;
   EventHandler* const handler_;
 
+  // Specified the device id of the output device to open or empty for the

[henrika (OOO until Aug 14), 2013/09/06 08:44:38]

Specified the device id of... sounds odd to me. Did you mean Specifies...

[tommi (sloooow) - chröme, 2013/09/06 11:01:35]

Yes, thanks, fixed.

+  // default output device.
+  const std::string output_device_id_;
+
   // Used by the unified IO to open the correct input device.
-  std::string input_device_id_;
+  const std::string input_device_id_;
 
   AudioOutputStream* stream_;
 
   // When non-NULL, audio is being diverted to this stream.
   AudioOutputStream* diverting_to_stream_;
 
   // The current volume of the audio stream.
   double volume_;
 
   // |state_| is written on the audio manager thread and is read on the
@@ skipping 23 matching lines @@
 
   // Periodic callback to report power levels during playback.
   base::CancelableClosure power_poll_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_