Previously we would suggest owners for the whole CL, rather than just
the files currently missing owner approval.

R=maruel@chromium.org
BUG=130978

Review URL: https://chromiumcodereview.appspot.com/23591064

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@224183 0039d316-1c4b-4281-b951-d872f2087c98