anchor.diff: -// Copyright (c) 2015, <your name>. All rights reserved. Use of this source code
  +// Copyright (c) 2015, Filip Hracek. 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:html';
   import 'dart:async';
  -import 'dart:convert';
   import 'dart:js';
   
   import 'package:firebase/firebase.dart';
  
positive.code: 
    @override
    onPushMessageUnsubscribe(PushSubscription subscription, bool success) async {
      subsPermissionDeniedEl.style.display = "none";
      // Even in case of failure, remove subscription from server.
      var subFirebaseRec = _subscriptionSet.child(subscription.subscriptionId);
      var snapshot = await subFirebaseRec.once("value");
  
negative.code:     });
    }
  
    void _upgradeSwitch() {
      new JsObject(context['MaterialSwitch'], [querySelector(".mdl-switch")]);
    }
  
    @override
    void onInitSuccess() {
      updatePushPermissionSwitch();
  