Update charted to 0.4.8 and roll

packages/observable/test/observable_test_utils.dart

Index: packages/observable/test/observable_test_utils.dart
diff --git a/packages/observable/test/observable_test_utils.dart b/packages/observable/test/observable_test_utils.dart
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+// Copyright (c) 2016, 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 observable.test.observable_test_utils;
+
+import 'dart:async';
+
+import 'package:observable/observable.dart';
+import 'package:test/test.dart';
+
+/// A small method to help readability. Used to cause the next "then" in a chain
+/// to happen in the next microtask:
+///
+///     future.then(newMicrotask).then(...)
+///
+/// Uses [mu].
+newMicrotask(_) => new Future.value();
+
+// TODO(jmesserly): use matchers when we have a way to compare ChangeRecords.
+// For now just use the toString.
+void expectChanges(actual, expected, {String reason}) =>
+    expect('$actual', '$expected', reason: reason);
+
+List<ListChangeRecord> getListChangeRecords(
+        List<ListChangeRecord> changes, int index) =>
+    new List.from(changes.where((ListChangeRecord c) => c.indexChanged(index)));
+
+List<PropertyChangeRecord> getPropertyChangeRecords(
+        List<ChangeRecord> changes, Symbol property) =>
+    new List.from(changes.where(
+        (ChangeRecord c) => c is PropertyChangeRecord && c.name == property));