anchor.diff:  class ScopeEvent {
     static final String DESTROY = 'ng-destroy';
   
  +  /**
  +   * Data attached to the event. This would be the optional parameter
  +   * from [Scope.emit] and [Scope.broadcast].
  +   */
     final data;
   
     /**
  
positive.code:   dynamic putIfAbsent(key, fn) => _scope.putIfAbsent(key, fn);
  }
  
  class Scope {
    final context;
    final RootScope rootScope;
    Scope _parentScope;
    Scope get parentScope => _parentScope;
  
    final WatchGroup watchGroup;
    final WatchGroup observeGroup;
    final int _depth;
  
negative.code:   final Scope targetScope;
  
    /**
     * The destination scope that intercepted the event. As
     * the event traverses the scope hierarchy the the event instance
     * stays the same, but the [currentScope] reflects the scope
     * of the current listener which is firing.
     */
    Scope get currentScope => _currentScope;
    Scope _currentScope;
  