if (nsnull != mStyleSheet) { PRInt32 count; mStyleSheet->StyleRuleCount(count); *aLength = (PRUint32)count; } else { *aLength = 0; }  return NS_OK; }
NS_ENSURE_ARG_POINTER(aLength);
CSSRuleListImpl::GetLength(PRUint32* aLength){  if (nsnull != mStyleSheet) {    PRInt32 count;    mStyleSheet->StyleRuleCount(count);    *aLength = (PRUint32)count;  }  else {    *aLength = 0;  }  return NS_OK;}