anchor.diff:      } else {
         _initialWritePending = true;
         _domService.scheduleWrite(() {
  +        _element.classes.toggle(_hideClassLegacy, !value);
           _element.classes.toggle(_hideClass, !value);
  +        _element.classes.toggle(_hiddenClassLegacy, !value);
           _element.classes.toggle(_hiddenClass, !value);
           _initialWritePending = false;
         });
  
positive.code:   void _hide() {
      _hiding = true;
      _domService.scheduleWrite(() {
        _element.classes.add(_hideClass);
        _onHide.add(_element);
      });
  
negative.code:   void _removeNgHide() {
      if (_hiding) return;
      _domService.scheduleWrite(() {
        _element.classes.remove(_hideClassLegacy);
        _element.classes.remove(_hideClass);
        _onShow.add(_element);
      });
  