BUG=None
TEST=Change files that need OWNERS review.  Upload the patch.  Check that the warning suggests a minimum set of reviewers.

Review URL: https://chromiumcodereview.appspot.com/10222020

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@135619 0039d316-1c4b-4281-b951-d872f2087c98