Add AudioManager::GetAudioOutputDeviceNames and implement for pulseaudio.

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 <string>
 
 #include "base/basictypes.h"
@@ skipping 46 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.
   virtual void GetAudioInputDeviceNames(AudioDeviceNames* device_names) = 0;
 
+  // Appends a list of available output devices to |device_names|,
+  // which must initially be empty.
+  virtual void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) = 0;
+
   // 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
   // audio source thinks it can usually fill without blocking. Internally two
   // or three buffers are created, one will be locked for playback and one will
   // be ready to be filled in the call to AudioSourceCallback::OnMoreData().
   //
   // To create a stream for the default output device, pass an empty string
   // for |device_id|, otherwise the specified audio device will be opened.
@@ skipping 91 matching lines @@
  protected:
   AudioManager();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_H_