anchor.diff:      _prefs.setValue('OutlineCollapsed', value);
     }
   
  -  void _addItem(OutlineItem item) {
  +  OutlineItem _addItem(OutlineItem item) {
       // Add leaf items to be used to find a position in the outline to scroll to
       // when the file in the editor is scrolled.
       _outlineItems.add(item);
  
positive.code:     }
    }
  
    void _create(services.OutlineTopLevelEntry data) {
      if (data is services.OutlineClass) {
        _addClass(data);
      } else if (data is services.OutlineTopLevelVariable) {
        _addVariable(data);
      } else if (data is services.OutlineTopLevelFunction) {
        _addFunction(data);
      } else if (data is services.OutlineTypeDef) {
        _addTypeDef(data);
      } else {
        throw new UnimplementedError("Unknown type");
      }
  
negative.code:     _postProcess();
    }
  
    OutlineClassMember _addItem(OutlineClassMember item) {
      _childrenRootElement.append(item.element);
      members.add(item);
      return item;
    }
  
    void _populate(services.OutlineClass classData) {
  