Add List.shuffle().

sdk/lib/_collection_dev/iterable.dart

Index: sdk/lib/_collection_dev/iterable.dart
diff --git a/sdk/lib/_collection_dev/iterable.dart b/sdk/lib/_collection_dev/iterable.dart
index 9e7b9902c8a67bda7d2aeef1b37d2f844c08e50b..58f580f3c3761c47e0a27a8bbc1013c68a15414b 100644
--- a/sdk/lib/_collection_dev/iterable.dart
+++ b/sdk/lib/_collection_dev/iterable.dart
@@ -953,6 +953,18 @@ class IterableMixinWorkaround {
     Sort.sort(list, compare);
   }
 
+  static void shuffleList(List list) {
+    Random random = new Random();
+    int length = list.length;
+    while (length > 1) {
+      int pos = random.nextInt(length);
+      length -= 1;
+      var tmp = list[length];
+      list[length] = list[pos];
+      list[pos] = tmp;
+    }
+  }
+
   static int indexOfList(List list, var element, int start) {
     return Arrays.indexOf(list, element, start, list.length);
   }