[PPAPI] Pepper MediaStream API audio track implementation and example.

ppapi/api/ppb_audio_frame.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_AudioFrame</code> interface.
  */
 
 [generate_thunk]
@@ skipping 30 matching lines @@
    *
    * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
    * resource.
    * @param[in] timestamp A <code>PP_TimeDelta</code> containing the timestamp
    * of the audio frame. Given in seconds since the start of the containing
    * audio stream.
    */
   void SetTimestamp([in] PP_Resource frame, [in] PP_TimeDelta timestamp);
 
   /**
+   * Gets the sample rate of the audio frame.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return The sample rate of the audio frame.
+   */
+  [on_failure=PP_AUDIOSAMPLERATE_NONE]
+  PP_AudioSampleRate GetSampleRate([in] PP_Resource frame);
+
+  /**
    * Gets the sample size of the audio frame.
    *
    * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
    * resource.
    *
    * @return The sample size of the audio frame.
    */
   uint32_t GetSampleSize([in] PP_Resource frame);
   
   /**
@@ skipping 31 matching lines @@
   /**
    * Gets the size of the data buffer in bytes.
    *
    * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
    * resource.
    *
    * @return The size of the data buffer in bytes.
    */
   uint32_t GetDataBufferSize([in] PP_Resource frame);
 };