merge
merge

R=harryjin@google.com
BUG=libyuv:448

Review URL: https://webrtc-codereview.appspot.com/52119004.

lyx2014/libyuv_free,lemenkov/libyuv,lyx2014/libyuv_free,lemenkov/libyuv,lyx2014/yuv,lyx2014/libyuv_free,lemenkov/libyuv,lemenkov/libyuv,lyx2014/yuv,lyx2014/libyuv_free,lyx2014/yuv,yarrcc/libyuv-ios,yarrcc/libyuv-ios,disigma/yuv,yarrcc/libyuv-ios,yarrcc/libyuv-ios,disigma/yuv,lyx2014/yuv,disigma/yuv