Remove deprecated string features.

tests/standalone/io/http_server_socket_test.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.
 
 import "dart:io";
 import "dart:isolate";
 import "dart:math";
 
 class ExpectedDataOutputStream implements OutputStream {
   ExpectedDataOutputStream(List<int> this._data,
@@ skipping 125 matching lines @@
   Function _onClosedInternal;
   List<int> _data;
   ExpectedDataOutputStream _outputStream;
 }
 
 class ServerSocketMock implements ServerSocket {
   ServerSocketMock(String addr, int this._port, int backlog) :
       _sockets = new Set<Socket>();
 
   void spawnSocket(var data, String response, int cutOff, bool closeAsError) {
-    if (data is String) data = data.charCodes;
+    if (data is String) data = data.codeUnits;
     SocketMock socket = new SocketMock(data,
-                                       response.charCodes,
+                                       response.codeUnits,
                                        cutOff,
                                        closeAsError);
     _sockets.add(socket);
     ReceivePort port = new ReceivePort();
     socket._onClosedInternal = () {
       // The server should always close the connection.
       _sockets.remove(socket);
       port.close();
     };
     // Tell HttpServer that a connection have come to life.
@@ skipping 69 matching lines @@
       "GET / HTTP/1.1\r\nKeep-Alive: False\r\n\r\n",
       "HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\nconnection: close"
       "\r\n\r\n0\r\n\r\n");
 
   server.close();
 }
 
 void main() {
   testSocketClose();
 }