nsAttributeContent* it = new nsAttributeContent;
nsAttributeContent* it = new nsAttributeContent();
NS_NewAttributeContent(nsIContent** aContent){  NS_ENSURE_ARG_POINTER(aContent);  nsAttributeContent* it = new nsAttributeContent;  if (!it) {    return NS_ERROR_OUT_OF_MEMORY;  }  return CallQueryInterface(it, aContent);}