anchor.diff: -// Copyright 2013 Google Inc. All Rights Reserved.
  +// Copyright 2014 Google Inc. All Rights Reserved.
   //
   // Licensed under the Apache License, Version 2.0 (the "License");
   // you may not use this file except in compliance with the License.
  
positive.code: class TreeIterator<V> implements BidirectionalIterator<V> {
  
    int _state;
    AvlNode<V> _current;
  
    final int _modCountGuard;
    final TreeSet<V> _tree;
  
negative.code:   TreeSet._(this.comparator);
  
    /**
     * Returns an [Iterator] that iterates over this tree, in reverse.
     */
    Iterator<V> get reversed;
  
    /**
     * Search the tree for the matching [object] or the [nearestOption]
  