nsCOMPtr<nsIContent> instance = new nsXMLStylesheetPI(aData, aOwnerDocument);
nsCOMPtr<nsIContent> instance = new nsXMLStylesheetPI(aData, nsnull);
NS_NewXMLStylesheetProcessingInstruction(nsIContent** aInstancePtrResult,                                         const nsAString& aData,                                         nsIDocument *aOwnerDocument){  *aInstancePtrResult = nsnull;    nsCOMPtr<nsIContent> instance = new nsXMLStylesheetPI(aData, aOwnerDocument);  if (!instance) {    return NS_ERROR_OUT_OF_MEMORY;  }  if (aOwnerDocument && !aOwnerDocument->AddOrphan(instance)) {    return NS_ERROR_OUT_OF_MEMORY;  }  instance.swap(*aInstancePtrResult);  return NS_OK;}