Support configuring number of audio buffers in MediaStream Pepper API.

ppapi/api/ppb_media_stream_audio_track.idl

 /* Copyright 2014 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.
  */
 
 /**
  * Defines the <code>PPB_MediaStreamAudioTrack</code> interface. Used for
  * receiving audio samples from a MediaStream audio track in the browser.
  */
 
@@ skipping 65 matching lines @@
   PP_Bool IsMediaStreamAudioTrack([in] PP_Resource resource);
 
   /**
    * Configures underlying buffers for incoming audio samples.
    * If the application doesn't want to drop samples, then the
    * <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS</code> should be
    * chosen such that inter-buffer processing time variability won't overrun all
    * the input buffers. If all buffers are filled, then samples will be
    * dropped. The application can detect this by examining the timestamp on
    * returned buffers. If <code>Configure()</code> is not called, default
-   * settings will be used.
+   * settings will be used. Calls to Configure while the plugin holds
+   * buffers will fail.
    * Example usage from plugin code:
    * @code
    * int32_t attribs[] = {
    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS, 4,
    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION, 10,
    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE};
    * track_if->Configure(track, attribs, callback);
    * @endcode
    *
    * @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
@@ skipping 94 matching lines @@
    * Closes the MediaStream audio track and disconnects it from the audio
    * source. After calling <code>Close()</code>, no new buffers will be
    * received.
    *
    * @param[in] audio_track A <code>PP_Resource</code> corresponding to a
    * MediaStream audio track resource.
    */
   void Close([in] PP_Resource audio_track);
 };