NS_ENSURE_ARG_POINTER(aInstancePtrResult);
NS_NewPrintContext(nsIPrintContext** aInstancePtrResult){  if (aInstancePtrResult == nsnull) {    return NS_ERROR_NULL_POINTER;  }  PrintContext *it = new PrintContext;  if (it == nsnull) {    return NS_ERROR_OUT_OF_MEMORY;  }  return it->QueryInterface(NS_GET_IID(nsIPrintContext), (void **) aInstancePtrResult);}