nsCOMPtr<nsIAtom> old(dont_AddRef(NS_NewAtom(aOldMedium)));
nsCOMPtr<nsIAtom> old = do_GetAtom(aOldMedium);
DOMMediaListImpl::Delete(const nsAString& aOldMedium){  if (aOldMedium.IsEmpty())    return NS_ERROR_DOM_NOT_FOUND_ERR;  nsCOMPtr<nsIAtom> old(dont_AddRef(NS_NewAtom(aOldMedium)));  NS_ENSURE_TRUE(old, NS_ERROR_OUT_OF_MEMORY);