NS_PRECONDITION(aDeclaration, "must have a declaration");
NS_NewCSSStyleRule(nsICSSStyleRule** aInstancePtrResult,                   nsCSSSelectorList* aSelector,                   nsCSSDeclaration* aDeclaration){  CSSStyleRuleImpl *it = new CSSStyleRuleImpl(aSelector, aDeclaration);  if (!it) {    return NS_ERROR_OUT_OF_MEMORY;  }  return CallQueryInterface(it, aInstancePtrResult);}