Make List.shuffle take an optional Random object to use.

runtime/lib/array.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.
 
 
 // TODO(srdjan): Use shared array implementation.
 class _List<E> implements List<E> {
   static final int _classId = (new _List(0))._cid;
 
   factory _List(length) native "List_allocate";
@@ skipping 184 matching lines @@
   }
 
   bool get isNotEmpty => !isEmpty;
 
   Iterable<E> get reversed => IterableMixinWorkaround.reversedList(this);
 
   void sort([int compare(E a, E b)]) {
     IterableMixinWorkaround.sortList(this, compare);
   }
 
-  void shuffle() {
-    IterableMixinWorkaround.shuffleList(this);
+  void shuffle([Random random]) {
+    IterableMixinWorkaround.shuffleList(this, random);
   }
 
   int indexOf(Object element, [int start = 0]) {
     return Arrays.indexOf(this, element, start, this.length);
   }
 
   int lastIndexOf(Object element, [int start = null]) {
     if (start == null) start = length - 1;
     return Arrays.lastIndexOf(this, element, start);
   }
@@ skipping 236 matching lines @@
 
   bool get isNotEmpty => !isEmpty;
 
   Iterable<E> get reversed => IterableMixinWorkaround.reversedList(this);
 
   void sort([int compare(E a, E b)]) {
     throw new UnsupportedError(
         "Cannot modify an immutable array");
   }
 
-  void shuffle() {
+  void shuffle([Random random]) {
     throw new UnsupportedError(
         "Cannot modify an immutable array");
   }
 
   String toString() {
     return IterableMixinWorkaround.toStringIterable(this, '[', ']');
   }
 
   int indexOf(Object element, [int start = 0]) {
     return Arrays.indexOf(this, element, start, this.length);
@@ skipping 84 matching lines @@
     }
     _position = _length;
     _current = null;
     return false;
   }
 
   E get current {
     return _current;
   }
 }