Replace string uses with code units in Json parser.

samples/buildbot/model.dart

 // Copyright (c) 2015, the Fletch 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.md file.
 
 import 'json.dart';
 
 class Resource {
   String host;
   String path;
   Resource(this.host, this.path);
@@ skipping 42 matching lines @@
 
   JsonData _status;
   JsonData _changes;
 
   Console(this.title,
           Resource api,
           Resource status) {
     _status = new JsonData(status.sub("/current?format=json"));
     _status.updateData();
     _changes = new JsonData(api.sub("/json/changes"));
+    _changes.updateData();
   }
 
   String get status {
     _status.ensureData();
     if (_status.data is Map && _status.data.containsKey("message")) {
       return _status.data['message'];
     }
     return "unknown status";
   }
 }