val urlHost = url.host
      if (domain == null) {
        domain = urlHost
      } else if (!domainMatch(urlHost, domain)) {
        return null // No domain match? This is either incompetence or malice!
      }

      // If the domain is a suffix of the url host, it must not be a public suffix.
      if (urlHost.length != domain.length &&
        PublicSuffixDatabase.get().getEffectiveTldPlusOne(domain) == null