Make String.charCodes a getter.

tests/standalone/io/http_read_test.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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 #import("dart:isolate");
@@ skipping 155 matching lines @@
     HttpClient httpClient = new HttpClient();
     void sendRequest() {
       HttpClientConnection conn =
           httpClient.post("127.0.0.1", port, "/echo");
       conn.onRequest = (HttpClientRequest request) {
         if (chunkedEncoding) {
           request.outputStream.writeString(data.substring(0, 10));
           request.outputStream.writeString(data.substring(10, data.length));
         } else {
           request.contentLength = data.length;
-          request.outputStream.write(data.charCodes());
+          request.outputStream.write(data.charCodes);
         }
         request.outputStream.close();
       };
       conn.onResponse = (HttpClientResponse response) {
         Expect.equals(HttpStatus.OK, response.statusCode);
         InputStream stream = response.inputStream;
         List<int> body = new List<int>();
         stream.onData = () {
           List tmp = new List(3);
           int bytes = stream.readInto(tmp);
@@ skipping 33 matching lines @@
     HttpClient httpClient = new HttpClient();
     void sendRequest() {
       HttpClientConnection conn =
           httpClient.post("127.0.0.1", port, "/echo");
       conn.onRequest = (HttpClientRequest request) {
         if (chunkedEncoding) {
           request.outputStream.writeString(data.substring(0, 10));
           request.outputStream.writeString(data.substring(10, data.length));
         } else {
           request.contentLength = data.length;
-          request.outputStream.write(data.charCodes());
+          request.outputStream.write(data.charCodes);
         }
         request.outputStream.close();
       };
       conn.onResponse = (HttpClientResponse response) {
         Expect.equals(HttpStatus.OK, response.statusCode);
         InputStream stream = response.inputStream;
         List<int> body = new List<int>();
         stream.onData = () {
           List tmp = stream.read(2);
           body.addAll(tmp);
@@ skipping 20 matching lines @@
   }
   testServerMain.start();
 }
 
 void main() {
   testReadInto(true);
   testReadInto(false);
   testReadShort(true);
   testReadShort(false);
 }