Add remotePort getter to Socket.

runtime/bin/socket.dart

 // 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.
 
 interface ServerSocket default _ServerSocket {
   /**
    * Constructs a new server socket, binds it to a given address and port,
    * and listens on it.
    */
   ServerSocket(String bindAddress, int port, int backlog);
@@ skipping 89 matching lines @@
    * Returns output stream of the socket.
    */
   OutputStream get outputStream();
 
   /**
    * Returns the port used by this socket.
    */
   int get port();
 
   /**
+   * Returns the remote port connected to by this socket.
+   */
+  int get remotePort();
+
+  /**
    * Closes the socket. Calling [close] will never throw an exception
    * and calling it several times is supported. If [halfClose] is true
    * the socket will only be closed for writing and it might still be
    * possible to read data. Calling [close] will not trigger a call to
    * [onClosed].
    */
   void close([bool halfClose]);
 
   /**
    * Socket is hashable.
@@ skipping 14 matching lines @@
         sb.add(" ($osError)");
       }
     } else if (osError != null) {
       sb.add(": $osError");
     }
     return sb.toString();
   }
   final String message;
   final OSError osError;
 }