Update charted to 0.4.8 and roll

packages/collection/test/equality_map_test.dart

+// 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:collection/collection.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test("uses the given equality", () {
+    var map = new EqualityMap(const IterableEquality());
+    expect(map, isEmpty);
+
+    map[[1, 2, 3]] = 1;
+    expect(map, containsPair([1, 2, 3], 1));
+
+    map[[1, 2, 3]] = 2;
+    expect(map, containsPair([1, 2, 3], 2));
+
+    map[[2, 3, 4]] = 3;
+    expect(map, containsPair([1, 2, 3], 2));
+    expect(map, containsPair([2, 3, 4], 3));
+  });
+
+  test("EqualityMap.from() prefers the lattermost equivalent key", () {
+    var map = new EqualityMap.from(const IterableEquality(), {
+      [1, 2, 3]: 1,
+      [2, 3, 4]: 2,
+      [1, 2, 3]: 3,
+      [2, 3, 4]: 4,
+      [1, 2, 3]: 5,
+      [1, 2, 3]: 6,
+    });
+
+    expect(map, containsPair([1, 2, 3], 6));
+    expect(map, containsPair([2, 3, 4], 4));
+  });
+}