Update charted to 0.4.8 and roll

packages/observe/benchmark/object_benchmark.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-library observe.test.benchmark.object_benchmark;
-
-import 'observation_benchmark_base.dart';
-import 'test_observable.dart';
-
-class ObjectBenchmark extends ObservationBenchmarkBase {
-  ObjectBenchmark(int objectCount, int mutationCount, String config) : super(
-          'ObjectBenchmark:$objectCount:$mutationCount:$config', objectCount,
-          mutationCount, config);
-
-  @override
-  int mutateObject(TestObservable obj) {
-    // Modify the first 5 properties.
-    obj.a++;
-    obj.b++;
-    obj.c++;
-    obj.d++;
-    obj.e++;
-    // Return # of modifications.
-    return 5;
-  }
-
-  @override
-  TestObservable newObject() => new TestObservable();
-}