Update charted to 0.4.8 and roll

packages/quiver/lib/src/collection/delegates/set.dart

Index: packages/quiver/lib/src/collection/delegates/set.dart
diff --git a/packages/quiver/lib/src/collection/delegates/set.dart b/packages/quiver/lib/src/collection/delegates/set.dart
index 87e3527230079dd97c1624962bb0ef4c351e72ee..9362e80737c3aca46b0c74ebf8a3254c085bfc60 100644
--- a/packages/quiver/lib/src/collection/delegates/set.dart
+++ b/packages/quiver/lib/src/collection/delegates/set.dart
@@ -14,18 +14,16 @@
 
 part of quiver.collection;
 
-/**
- * An implementation of [Set] that delegates all methods to another [Set].
- * For instance you can create a FruitSet like this :
- *
- *     class FruitSet extends DelegatingSet<Fruit> {
- *       final Set<Fruit> _fruits = new Set<Fruit>();
- *
- *       Set<Fruit> get delegate => _fruits;
- *
- *       // custom methods
- *     }
- */
+/// An implementation of [Set] that delegates all methods to another [Set].
+/// For instance you can create a FruitSet like this :
+///
+///     class FruitSet extends DelegatingSet<Fruit> {
+///       final Set<Fruit> _fruits = new Set<Fruit>();
+///
+///       Set<Fruit> get delegate => _fruits;
+///
+///       // custom methods
+///     }
 abstract class DelegatingSet<E> extends DelegatingIterable<E>
     implements Set<E> {
   Set<E> get delegate;
@@ -38,7 +36,7 @@ abstract class DelegatingSet<E> extends DelegatingIterable<E>
 
   bool containsAll(Iterable<Object> other) => delegate.containsAll(other);
 
-  Set<E> difference(Set<E> other) => delegate.difference(other);
+  Set<E> difference(Set<Object> other) => delegate.difference(other);
 
   Set<E> intersection(Set<Object> other) => delegate.intersection(other);