Currently no one is using this but will be used soon.

BUG=164248
R=dewittj@chromium.org, jhawkins@chromium.org

Review URL: https://codereview.chromium.org/15896033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@203991 0039d316-1c4b-4281-b951-d872f2087c98