NS_ENSURE_ARG_POINTER(aParent);  if (!mRule) { *aParent = nsnull;
if (!Rule()) { *aParentRule = nsnull;
DOMCSSDeclarationImpl::GetParentRule(nsIDOMCSSRule **aParent){  NS_ENSURE_ARG_POINTER(aParent);  if (!mRule) {    *aParent = nsnull;    return NS_OK;  }  return mRule->GetDOMRule(aParent);}