NS_ENSURE_ARG_POINTER(parent);
nsCOMPtr<nsIDocShellTreeItem> parent; NS_ENSURE_SUCCESS(GetSameTypeParent(getter_AddRefs(parent)), NS_ERROR_FAILURE);
NS_IMETHODIMP nsWebShell::GetParent(nsIDocShellTreeItem** parent){   NS_ENSURE_ARG_POINTER(parent);   *parent = mParent;   NS_IF_ADDREF(*parent);   return NS_OK;}