if (nsnull == it) {
if (!it) {
NS_NewAttributeContent(nsIContent** aContent){  NS_PRECONDITION(aContent, "null OUT ptr");  if (nsnull == aContent) {    return NS_ERROR_NULL_POINTER;  }  nsAttributeContent* it = new nsAttributeContent;  if (nsnull == it) {    return NS_ERROR_OUT_OF_MEMORY;  }  return NS_SUCCEEDED(it->QueryInterface(NS_GET_IID(nsIContent), (void **)aContent)) ?         NS_OK : NS_ERROR_FAILURE;}