aPublicId, aSystemId, EmptyString());
aPublicId, aSystemId, nsString());
nsDOMImplementation::CreateDocumentType(const nsAString& aQualifiedName,                                        const nsAString& aPublicId,                                        const nsAString& aSystemId,                                        nsIDOMDocumentType** aReturn){  *aReturn = nsnull;  nsresult rv = nsContentUtils::CheckQName(aQualifiedName);  NS_ENSURE_SUCCESS(rv, rv);  nsCOMPtr<nsIAtom> name = do_GetAtom(aQualifiedName);  NS_ENSURE_TRUE(name, NS_ERROR_OUT_OF_MEMORY);  return NS_NewDOMDocumentType(aReturn, name, nsnull, nsnull,                               aPublicId, aSystemId, EmptyString());}