ref: df2314cfdd1ea6c0b4bca77165d959b74b58e4bb
parent: f954490bbf24af9431f9c24744aef1476e11acef
author: Jim Bankoski <jimbankoski@google.com>
date: Wed Jun 19 07:05:34 EDT 2013
don't copy partitions for key frames or altrefs force us to go through slow partitioning for keyframes, altref and overlays. Change-Id: I1a286361bf74083e71973575a7296be46eb98742