[PPAPI][MediaStream] Rename AudioFrame to AudioBuffer

ppapi/examples/media_stream_video/media_stream_video.cc

Index: ppapi/examples/media_stream_video/media_stream_video.cc
diff --git a/ppapi/examples/media_stream_video/media_stream_video.cc b/ppapi/examples/media_stream_video/media_stream_video.cc
index b23f3eddbe8e91e11a66360904ee0d8012917d73..3635e0e8cd89b8d257bec28f016aa0630d80fd75 100644
--- a/ppapi/examples/media_stream_video/media_stream_video.cc
+++ b/ppapi/examples/media_stream_video/media_stream_video.cc
@@ -342,7 +342,7 @@ void MediaStreamVideoDemoInstance::OnGetFrame(
     return;
   const char* data = static_cast<const char*>(frame.GetDataBuffer());
   pp::Size size;
-  PP_DCHECK(frame.GetSize(&size));
+  frame.GetSize(&size);
 
   if (size != frame_size_) {
     frame_size_ = size;