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

third_party/pkg/js/lib/src/wrapping/js/array_to_list_adapter.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.
 
 part of js.wrapping;
 
 /// Adapter to handle a js array as a dart [List].
 /// You can provide a translator to automatically wrap contained Proxy to some
 /// TypedProxy or something else.
 class JsArrayToListAdapter<E> extends TypedProxy /*with ListMixin<E>*/ implements List<E> {
@@ skipping 34 matching lines @@
   }
   @override void operator []=(int index, E value) {
     if (index < 0 || index >= this.length) throw new RangeError.value(index);
     $unsafe[index] = _toJs(value);
   }
   @override void set length(int length) { $unsafe.length = length; }
   @override void sort([int compare(E a, E b)]) {
     final sortedList = _asList()..sort(compare);
     setRange(0, sortedList.length, sortedList);
   }
-  @override void shuffle() {
-    final shuffledList = _asList()..shuffle();
+  @override void shuffle([Random random]) {
+    final shuffledList = _asList()..shuffle(random);
     setRange(0, shuffledList.length, shuffledLength);
   }
   @override void insert(int index, E element) {
     $unsafe.splice(index, 0, _toJs(element));
   }
   @override E removeAt(int index) {
     if (index < 0 || index >= this.length) throw new RangeError.value(index);
     return _fromJs($unsafe.splice(index, 1)[0]);
   }
   @override E removeLast() => _fromJs($unsafe.pop());
@@ skipping 480 matching lines @@
   // Iterator
   @override bool moveNext() {
     if (_currentIndex + 1 < length) {
       _currentIndex++;
       return true;
     }
     return false;
   }
   @override E get current => _jsArray[_currentIndex];
 }