Introduce AudioOutputResampler for browser side resampling.

media/audio/audio_manager_base.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_BASE_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 62 matching lines @@
 
   // Creates the input stream for the |AUDIO_PCM_LINEAR| format. The legacy
   // name is also from |AUDIO_PCM_LINEAR|.
   virtual AudioInputStream* MakeLinearInputStream(
       const AudioParameters& params, const std::string& device_id) = 0;
 
   // Creates the input stream for the |AUDIO_PCM_LOW_LATENCY| format.
   virtual AudioInputStream* MakeLowLatencyInputStream(
       const AudioParameters& params, const std::string& device_id) = 0;
 
+  // Returns the preferred hardware audio output parameters for opening output
+  // streams in the |AUDIO_PCM_LOW_LATENCY| format.
+  // TODO(dalecurtis): Retrieve the |channel_layout| value from hardware instead
+  // of accepting the value.
+  // TODO(dalecurtis): Each AudioManager should implement their own version, see
+  // http://crbug.com/137326
+  virtual AudioParameters GetPreferredLowLatencyOutputStreamParameters(
+      ChannelLayout channel_layout);
+
  protected:
   AudioManagerBase();
 
   typedef std::map<AudioParameters, scoped_refptr<AudioOutputDispatcher>,
                    AudioParameters::Compare>
       AudioOutputDispatchersMap;
 
   // Shuts down the audio thread and releases all the audio output dispatchers
   // on the audio thread.  All audio streams should be freed before
   // Shutdown is called.
@@ skipping 30 matching lines @@
 
   // Number of currently open input streams.
   int num_input_streams_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_