Revert "Convert HashSet, LinkedHashSet to factory methods and custom implementations."

sdk/lib/core/list.dart

 // Copyright (c) 2012, 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.
 
 part of dart.core;
 
 /**
  * An indexable collection of objects with a length.
  *
  * Subclasses of this class implement different kinds of lists.
@@ skipping 174 matching lines @@
    * If [start] is not provided, it defaults to [:this.length - 1:].
    *
    * Returns -1 if [element] is not found.
    */
   int lastIndexOf(E element, [int start]);
 
   /**
    * Removes all objects from this list;
    * the length of the list becomes zero.
    *
-   * Throws an [UnsupportedError], and retains all objects, if this
+   * Throws an [UnsupportedError], and retains all objects, if this 
    * is a fixed-length list.
    */
   void clear();
 
   /**
    * Inserts the object at position [index] in this list.
    *
    * This increases the length of the list by one and shifts all objects
    * at or after the index towards the end of the list.
    *
@@ skipping 160 matching lines @@
 
   /**
    * Returns an unmodifiable [Map] view of `this`.
    *
    * The map uses the indices of this list as keys and the corresponding objects
    * as values. The `Map.keys` [Iterable] iterates the indices of this list
    * in numerical order.
    */
   Map<int, E> asMap();
 }