Make String.charCodes a getter.

tests/standalone/io/regress-1925.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.
 //
 // Regression test for http://code.google.com/p/dart/issues/detail?id=1925.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
@@ skipping 21 matching lines @@
 
 class Regress1925Test extends TestingServerTest {
   Regress1925Test.start() : super.start(new Regress1925TestServer());
 
   void run() {
 
     var count = 0;
     var buffer = new List(5);
     Socket socket = new Socket(TestingServer.HOST, _port);
     socket.onConnect = () {
-      socket.outputStream.write("12345".charCodes());
+      socket.outputStream.write("12345".charCodes);
       socket.outputStream.close();
       socket.inputStream.onData = () {
         count += socket.inputStream.readInto(buffer, count);
       };
       socket.inputStream.onClosed = () {
         Expect.equals(5, count);
         shutdown();
       };
       socket.inputStream.onError = (e) => Expect.fail("Socket error $e");
     };
   }
 }
 
 main() {
   Regress1925Test test = new Regress1925Test.start();
 }