Revert "Dartium w/ JsInterop enabled"

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 141 matching lines @@
   int get length;
 
   /**
    * Changes the length of this list.
    *
    * If [newLength] is greater than
    * the current length, entries are initialized to [:null:].
    *
    * Throws an [UnsupportedError] if the list is fixed-length.
    */
-  set length(int newLength);
+  void set length(int newLength);
 
   /**
    * Adds [value] to the end of this list,
    * extending the length by one.
    *
    * Throws an [UnsupportedError] if the list is fixed-length.
    */
   void add(E value);
 
   /**
@@ skipping 293 matching lines @@
    * as values. The `Map.keys` [Iterable] iterates the indices of this list
    * in numerical order.
    *
    *     List<String> words = ['fee', 'fi', 'fo', 'fum'];
    *     Map<int, String> map = words.asMap();
    *     map[0] + map[1];   // 'feefi';
    *     map.keys.toList(); // [0, 1, 2, 3]
    */
   Map<int, E> asMap();
 }