The idea here is that we avoid updating all site data in SiteDataManager.jsm
just for checking a single host/origin and that we optimize performance by prioritizing
the most common data type (cookies) and synchronous lookups (AppCache) and returning
early if any data was found.
We will still refresh the site data list for clearing once the user clicks on "Clear Site Data".
Differential Revision: https://phabricator.services.mozilla.com/D42800
--HG--
extra : moz-landing-system : lando
