Remove usage of dart:json.

samples/swarm/UIState.dart

 // Copyright (c) 2011, 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.
 
 part of swarmlib;
 
 /**
  * The base class for UI state that intends to support browser history.
  */
 abstract class UIState {
@@ skipping 17 matching lines @@
       }
 
       if (firstEvent && state != '') {
         // TODO(jmesserly): When loading a bookmark or refreshing, we replace
         // the app state with a clean app state so the back button works. It
         // would be better to support jumping to the previous story.
         // We'd need to do some history manipulation here and some fixes to
         // the views for this.
         window.history.replaceState(null, document.title, '#');
       } else if (state != '') {
-        loadFromHistory(json.parse(state));
+        loadFromHistory(JSON.decode(state));
       }
       firstEvent = false;
     });
 
     _historyTracking = window.onPopState.listen(handler);
   }
 
   void stopHistoryTracking() {
     if (_historyTracking != null) {
       _historyTracking.cancel();
     }
   }
 
   /** Pushes a state onto the browser history stack */
   void pushToHistory() {
     if (_historyTracking == null) {
       throw 'history tracking not started';
     }
 
-    String state = json.stringify(toHistory());
+    String state = JSON.encode(toHistory());
 
     // TODO(jmesserly): [state] should be an Object, and we should pass it to
     // the state parameter instead of as a #hash URL. Right now we're working
     //  around b/4582542.
     window.history.pushState(null, '${document.title}#$state');
   }
 
   /**
    * Serialize the state to a form suitable for storing in browser history.
    */
   Map<String, String> toHistory();
 
   /**
    * Load the UI state from the given [values].
    */
   void loadFromHistory(Map<String, String> values);
 }