nsIDOMNode** aReturn) { return NS_ERROR_FAILURE;
nsIDOMNode** aReturn) { return nsGenericElement::doReplaceChild(aNewChild, aOldChild, aReturn);
  NS_METHOD ReplaceChild(nsIDOMNode* aNewChild, nsIDOMNode* aOldChild,                        nsIDOMNode** aReturn) {    return NS_ERROR_FAILURE;  }