BUG=none
TEST=out\release\libyuv_unittest --gtest_filter=*ARGBMirror*
Review URL: https://webrtc-codereview.appspot.com/1159005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@594 16f28f9a-4ce2-e073-06de-1de4eb20be90