BUG=271
TESTED=ARGBShuffle unittest
R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2320005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@804 16f28f9a-4ce2-e073-06de-1de4eb20be90