I'm trying to get a callback for every site that accesses any form of non-cookie storage. Which is the best algorithm to monkey patch from the Storage spec? I'm considering "obtain a storage key", but I'm not clear on the flow. Is this algorithm called once the first time an origin accesses local or session storage, and never before then? Also, could the browser run this algorithm for a non-site reason?

CC @inexorabletash @asutherland