/** Mark certificate chain as trusted. */
 public void trustCertificateChain(List trustedChain) {
   if (trustedCerts == null) {
     trustedCerts = new ArrayList(untrustedCerts.size());
   }
   trustedCerts.add(trustedChain);
   untrustedCerts.remove(trustedChain);
   if (untrustedCerts.isEmpty()) {
     untrustedCerts = null;
   }
 }