Add a CanonicalizedMap class to pkg/collection.

pkg/collection/lib/wrappers.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Delegating wrappers for [Iterable], [List], [Set], [Queue] and [Map].
  *
  * Also adds unmodifiable views for `Set` and `Map`, and a fixed length
  * view for `List`. The unmodifable list view from `dart:collection` is exported
  * as well, just for completeness.
  */
 library dart.pkg.collection.wrappers;
 
 import "dart:collection";
 import "dart:math" show Random;
 
 export "dart:collection" show UnmodifiableListView;
 
+export "src/canonicalized_map.dart";
 part "src/unmodifiable_wrappers.dart";
 
 /**
  * A base class for delegating iterables.
  *
  * Subclasses can provide a [_base] that should be delegated to. Unlike
  * [DelegatingIterable], this allows the base to be created on demand.
  */
 abstract class _DelegatingIterableBase<E> implements Iterable<E> {
   Iterable<E> get _base;
@@ skipping 531 matching lines @@
    * Returns a new set which contains all the elements of [this] and [other].
    *
    * That is, the returned set contains all the elements of this [Set] and all
    * the elements of [other].
    *
    * Note that the returned set will use the default equality operation, which
    * may be different than the equality operation [this] uses.
    */
   Set<V> union(Set<V> other) => toSet()..addAll(other);
 }