roll libyuv to r915 for webview jpeg build fix and NaCL pepper_33 initial support.
BUG=none
TEST=try bots
R=mflodman@chromium.org

Review URL: https://codereview.chromium.org/117083002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241326 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241327 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241327