nsCOMPtr<nsIBindableContent> bindable = do_QueryInterface(aContent);
nsCOMPtr<nsIBindableContent> bindable(do_QueryInterface(aContent));
nsXBLService::GetBaseTag(nsIContent* aContent, nsIAtom** aResult){  *aResult = nsnull;  nsCOMPtr<nsIBindableContent> bindable = do_QueryInterface(aContent);  if (!bindable)    return NS_ERROR_FAILURE;  return bindable->GetBaseTag(aResult);}