if (NS_FAILED(pl->SetValueAsString(value))) { NS_RELEASE(pl); return NS_ERROR_FAILURE; }
NS_NewSVGLength(nsISVGLength** result,                float value,                PRUint16 unit){  nsSVGLength *pl = new nsSVGLength(value, unit);  NS_ENSURE_TRUE(pl, NS_ERROR_OUT_OF_MEMORY);  NS_ADDREF(pl);  *result = pl;  return NS_OK;}