Add missing entry for Media.VideoPixelFormat's YV12J in histograms.xml

Review URL: https://codereview.chromium.org/148443004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247391 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247391