Add secure sockets to dart:io

lib/io/tls_socket.dart

Index: lib/io/tls_socket.dart
diff --git a/lib/io/tls_socket.dart b/lib/io/tls_socket.dart
new file mode 100644
index 0000000000000000000000000000000000000000..4ce8bc1d88e1ef69d1f6f70f4dc132f32039d560
--- /dev/null
+++ b/lib/io/tls_socket.dart
@@ -0,0 +1,20 @@
+// Copyright (c) 2012, 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.
+
+abstract class TlsSocket implements Socket {
+  /**
+   * Constructs a new secure socket and connect it to the given
+   * host on the given port. The returned socket is not yet connected
+   * but ready for registration of callbacks.
+   */
+  external factory TlsSocket(String host, int port);
+
+  /**
+   * Initializes the TLS library with the path to a certificate database
+   * containing root certificates for verifying certificate paths on
+   * client connections, and server certificates to provide on server
+   * connections.
+   */
+  external static void setCertificateDatabase(String pkcertDirectory);
+}