Merge "media: document MediaFormat.KEY_FRAME_RATE better" into nyc-dev am: 017567ae1d
am: 7d7f8f2724

* commit '7d7f8f27249b6655dd449d55759c4e0a36918043':
  media: document MediaFormat.KEY_FRAME_RATE better

Change-Id: I77702dde4ed2d8609f205eb7cf461fb382ea5751