Add SecureSocket.addCertificate.

tests/standalone/io/certificate_test_client.dart

+// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Client that tests that a certificate authority certificate loaded
+// at runtime can be used to verify a certificate chain. The server it
+// connects to uses localhost_cert, signed by myauthority_cert, to connect
+// securely.
+
+import 'dart:io';
+
+void main() {
+  int port = int.parse(new Options().arguments[0]);
+  String certificate = new Options().arguments[1];
+  SecureSocket.initialize();
+  var mycert = new File(certificate).readAsBytesSync();
+  bool threw = false;
+  try {
+    SecureSocket.addCertificate("I am not a cert".codeUnits,
+                                SecureSocket.TRUST_ISSUE_SERVER_CERTIFICATES);
+  } on CertificateException catch (e) {
+    threw = true;
+  }
+  if (!threw) throw new AssertException("Expected bad certificate to throw");
+
+  threw = false;
+  try {
+    SecureSocket.addCertificate(mycert, "Trust me, I'm a string");
+  } on CertificateException catch (e) {
+    threw = true;
+  }
+  if (!threw) throw new AssertException("Expected bad trust string to throw");
+
+  SecureSocket.addCertificate(mycert,
+                              SecureSocket.TRUST_ISSUE_SERVER_CERTIFICATES);
+  SecureSocket.connect('localhost', port).then((SecureSocket socket) {
+    socket.writeln("hello world");
+    socket.listen((data) { });
+    socket.close();
+  });
+}