Add List.shuffle().

pkg/unmodifiable_collection/lib/unmodifiable_collection.dart

Index: pkg/unmodifiable_collection/lib/unmodifiable_collection.dart
diff --git a/pkg/unmodifiable_collection/lib/unmodifiable_collection.dart b/pkg/unmodifiable_collection/lib/unmodifiable_collection.dart
index b94a0c46c0f8331b38fa6a8fae36a746ebcdc2da..2388ccb845ed3f02006de71a02bba908fb012088 100644
--- a/pkg/unmodifiable_collection/lib/unmodifiable_collection.dart
+++ b/pkg/unmodifiable_collection/lib/unmodifiable_collection.dart
@@ -54,11 +54,12 @@ class NonGrowableListView<E> extends _IterableView<E>
 
   Map<int, E> asMap() => _source.asMap();
 
-
   void operator []=(int index, E value) { _source[index] = value; }
 
   void sort([int compare(E a, E b)]) { _source.sort(compare); }
 
+  void shuffle() { _source.shuffle(); }
+
   void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) {
     _source.setRange(start, end, iterable, skipCount);
   }
@@ -154,7 +155,7 @@ class NonGrowableListView<E> extends _IterableView<E>
 /**
  * An unmodifiable set.
  *
- * An UnmodifiableSetView contains a [Set] object and ensures 
+ * An UnmodifiableSetView contains a [Set] object and ensures
  * that it does not change.
  * Methods that would change the set,
  * such as [add] and [remove], throw an [UnsupportedError].
@@ -230,7 +231,7 @@ class UnmodifiableSetView<E> extends _IterableView<E>
 /**
  * An unmodifiable map.
  *
- * An UnmodifiableMapView contains a [Map] object and ensures 
+ * An UnmodifiableMapView contains a [Map] object and ensures
  * that it does not change.
  * Methods that would change the map,
  * such as [addAll] and [remove], throw an [UnsupportedError].