[NOT FOR REVIEW][PPAPI] Implement MediaStreamVideoTrack pepper API

ppapi/cpp/media_stream_video_track.h

 // 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.
 
 #ifndef PPAPI_CPP_MEDIA_STREAM_VIDEO_TRACK_H_
 #define PPAPI_CPP_MEDIA_STREAM_VIDEO_TRACK_H_
 
 #include <string>
 
 #include "ppapi/c/pp_stdint.h"
@@ skipping 60 matching lines @@
 
   /// Gets the next video frame from the MediaStream track.
   /// If internal processing is slower than the incoming frame rate, new frames
   /// will be dropped from the incoming stream. Once the input buffer is full,
   /// frames will be dropped until <code>RecycleFrame()</code> is called to free
   /// a spot for another frame to be buffered.
   /// If there are no frames in the input buffer,
   /// <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the
   /// <code>callback</code> will be called, when a new frame is received or some
   /// error happens.
-  /// If the caller holds a frame returned by the previous call of
-  /// <code>GetFrame()</code>, <code>PP_ERROR_INPROGRESS</code> will be
-  /// returned. The caller should recycle the previous frame before getting
-  /// the next frame.
   ///
   /// @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
   /// completion of <code>GetFrame()</code>. If success, a VideoFrame will be
   /// passed into the completion callback function.
   ///
   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
   /// Returns PP_ERROR_NOMEMORY if <code>max_buffered_frames</code> frames
   /// buffer was not allocated successfully.
   int32_t GetFrame(
       const CompletionCallbackWithOutput<VideoFrame>& callback);
@@ skipping 18 matching lines @@
   ///
   /// @param[in] resource A <code>Resource</code> to test.
   ///
   /// @return True if <code>resource</code> is a MediaStream video track.
   static bool IsMediaStreamVideoTrack(const Resource& resource);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_MEDIA_STREAM_VIDEO_TRACK_H_