libyuv roll to r978
BUG=none
TEST=none

Review URL: https://codereview.chromium.org/150773003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248084 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248085 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248085