anchor.diff:  
         _nextTickCompleter.complete();
         _nextTickCompleter = null;
  -      _runTasks();
  +      _currentTasks.run();
   
         clock++;
         flags &= ~tickRunningFlag;
  
positive.code:   bool get isRunning => ((flags & runningFlags) != 0);
    bool get isFrameRunning => ((flags & frameRunningFlag) != 0);
  
    Queue<Function> _currentTasks = new Queue<Function>();
  
    ZoneSpecification _zoneSpec;
    Zone _zone;
  
negative.code:     }
    }
  
    void _requestAnimationFrame() {
      if ((flags & framePendingFlag) == 0) {
        html.window.requestAnimationFrame(_handleAnimationFrame);
  