Add remotePort getter to Socket.

tests/standalone/src/io/SocketPortTest.dart

Index: tests/standalone/src/io/SocketPortTest.dart
===================================================================
--- tests/standalone/src/io/SocketPortTest.dart	(revision 0)
+++ tests/standalone/src/io/SocketPortTest.dart	(revision 0)
@@ -0,0 +1,23 @@
+// 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.
+
+#import("dart:io");
+
+void testPort() {
+  ServerSocket server = new ServerSocket("127.0.0.1", 0, 5);
+
+  Socket clientSocket = new Socket("127.0.0.1", server.port);
+
+  server.onConnection = (Socket socket) {
+    Expect.equals(socket.port, server.port);
+    Expect.equals(clientSocket.port, socket.remotePort);
+    Expect.equals(clientSocket.remotePort, socket.port);
+
+    server.close();
+  };
+}
+
+void main() {
+  testPort();
+}