Add List.shuffle().

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index f1199d07ee0e547c598b4b55d8219c374c04b211..41ce9b061d7d78256c2114e1c70797bae796927b 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -8071,6 +8071,10 @@ class _ChildrenElementList extends ListBase<Element> {
     throw new UnsupportedError('Cannot sort element lists');
   }
 
+  void shuffle() {
+    throw new UnsupportedError('Cannot shuffle element lists');
+  }
+
   void removeWhere(bool test(Element element)) {
     _filter(test, false);
   }
@@ -8516,6 +8520,10 @@ class _FrozenElementList<T extends Element> extends ListBase<T> implements Eleme
     throw new UnsupportedError('Cannot sort list');
   }
 
+  void shuffle() {
+    throw new UnsupportedError('Cannot shuffle list');
+  }
+
   Element get first => _nodeList.first;
 
   Element get last => _nodeList.last;
@@ -17661,6 +17669,10 @@ class _ChildNodeListLazy extends ListBase<Node> {
     throw new UnsupportedError("Cannot sort Node list");
   }
 
+  void shuffle() {
+    throw new UnsupportedError("Cannot shuffle Node list");
+  }
+
   // FIXME: implement these.
   void setRange(int start, int end, Iterable<Node> iterable,
                 [int skipCount = 0]) {
@@ -29300,6 +29312,10 @@ abstract class ImmutableListMixin<E> implements List<E> {
     throw new UnsupportedError("Cannot sort immutable List.");
   }
 
+  void shuffle() {
+    throw new UnsupportedError("Cannot shuffle immutable List.");
+  }
+
   void insert(int index, E element) {
     throw new UnsupportedError("Cannot add to immutable List.");
   }