Update charted to 0.4.8 and roll

packages/collection/test/utils.dart

Index: packages/collection/test/utils.dart
diff --git a/packages/collection/test/utils.dart b/packages/collection/test/utils.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d8ab0829d942111586c0aa308abdf61659fdf49a
--- /dev/null
+++ b/packages/collection/test/utils.dart
@@ -0,0 +1,7 @@
+// 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.
+
+import "package:test/test.dart";
+
+final Matcher throwsCastError = throwsA(new isInstanceOf<CastError>());