nsIURIKey key(uri);    mPrototypeTable.Put(&key, aDocument);
mPrototypeTable.Put(uri, aDocument);
nsXULPrototypeCache::PutPrototype(nsIXULPrototypeDocument* aDocument){    nsresult rv;    nsCOMPtr<nsIURI> uri;    rv = aDocument->GetURI(getter_AddRefs(uri));    nsIURIKey key(uri);    // Put() w/o  a third parameter with a destination for the    // replaced value releases it    mPrototypeTable.Put(&key, aDocument);    return NS_OK;}