Update charted to 0.4.8 and roll

packages/observe/benchmark/test_observable.dart

Index: packages/observe/benchmark/test_observable.dart
diff --git a/packages/observe/benchmark/test_observable.dart b/packages/observe/benchmark/test_observable.dart
deleted file mode 100644
index 11838008604f1d295f81056c1b09ac9dd233cd38..0000000000000000000000000000000000000000
--- a/packages/observe/benchmark/test_observable.dart
+++ /dev/null
@@ -1,24 +0,0 @@
-// 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.test_observable;
-
-import 'package:observe/observe.dart';
-
-class TestObservable extends Observable {
-  @observable int a = 0;
-  @observable int b = 0;
-  @observable int c = 0;
-  @observable int d = 0;
-  @observable int e = 0;
-  @observable int f = 0;
-  @observable int g = 0;
-  @observable int h = 0;
-  @observable int i = 0;
-  @observable int j = 0;
-  @observable int k = 0;
-  @observable int l = 0;
-  @observable int m = 0;
-  @observable int n = 0;
-  @observable int o = 0;
-}