Update charted to 0.4.8 and roll

packages/quiver/test/collection/delegates/set_test.dart

 // Copyright 2013 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 45 matching lines @@
     test('containsAll', () {
       expect(delegatingSet.containsAll(['a', 'cc']), isTrue);
       expect(delegatingSet.containsAll(['a', 'c']), isFalse);
     });
 
     test('difference', () {
       expect(delegatingSet.difference(new Set<String>.from(['a', 'cc'])),
           equals(['b']));
       expect(delegatingSet.difference(new Set<String>.from(['cc'])),
           equals(['a', 'b']));
-    }, skip: "Test failing: Caught type 'LinkedHashSet<String>' is not a subtype of type 'HashSet<String>' of 'result'.");
+    });
 
     test('intersection', () {
       expect(delegatingSet.intersection(new Set<String>.from(['a', 'dd'])),
           equals(['a']));
       expect(
           delegatingSet.intersection(new Set<String>.from(['e'])), equals([]));
     });
 
     test('remove', () {
       expect(delegatingSet.remove('b'), isTrue);
@@ skipping 20 matching lines @@
       expect(delegatingSet, equals(['a', 'b']));
     });
 
     test('union', () {
       expect(
           delegatingSet.union(new LinkedHashSet<String>.from(['a', 'cc', 'd'])),
           equals(['a', 'b', 'cc', 'd']));
     });
   });
 }