Update charted to 0.4.8 and roll

packages/observe/benchmark/setup_path_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.setup_path_benchmark;
-
-import 'package:observe/observe.dart';
-import 'setup_observation_benchmark_base.dart';
-import 'test_path_observable.dart';
-
-class SetupPathBenchmark extends SetupObservationBenchmarkBase {
-  final PropertyPath path = new PropertyPath('foo.bar.baz');
-
-  SetupPathBenchmark(int objectCount, String config)
-      : super('SetupPathBenchmark:$objectCount:$config', objectCount, config);
-
-  @override
-  TestPathObservable newObject() => new TestPathObservable(1);
-
-  @override
-  PathObserver newObserver(TestPathObservable obj) =>
-      new PathObserver(obj, path)..open(() {});
-}