anchor.diff:  
   class OutlineClass extends OutlineTopLevelItem {
     html.UListElement _childrenRootElement = new html.UListElement();
  -
     List<OutlineClassMember> members = [];
  -  StreamController childSelectedController = new StreamController();
  -  Stream get onChildSelected => childSelectedController.stream;
   
     OutlineClass(services.OutlineClass data)
         : super(data, "class") {
  
positive.code:     }
    }
  
    OutlineTopLevelItem _create(services.OutlineTopLevelEntry data) {
      if (data is services.OutlineClass) {
        return _addClass(data);
      } else if (data is services.OutlineTopLevelVariable) {
        return _addVariable(data);
      } else if (data is services.OutlineTopLevelFunction) {
        return _addFunction(data);
      } else {
        throw new UnimplementedError("Unknown type");
      }
  
negative.code:     }
    }
  
    void _createMember(services.OutlineEntry data) {
      if (data is services.OutlineMethod) {
        return addMethod(data);
      } else if (data is services.OutlineProperty) {
  