Update charted to 0.4.8 and roll

packages/collection/lib/src/equality_set.dart

Index: packages/collection/lib/src/equality_set.dart
diff --git a/packages/collection/lib/src/equality_set.dart b/packages/collection/lib/src/equality_set.dart
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+++ b/packages/collection/lib/src/equality_set.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.
+
+import 'dart:collection';
+
+import 'equality.dart';
+import 'wrappers.dart';
+
+/// A [Map] whose key equality is determined by an [Equality] object.
+class EqualitySet<E> extends DelegatingSet<E> {
+  /// Creates a set with equality based on [equality].
+  EqualitySet(Equality<E> equality)
+      : super(new LinkedHashSet(
+            equals: equality.equals,
+            hashCode: equality.hash,
+            isValidKey: equality.isValidKey));
+
+  /// Creates a set with equality based on [equality] that contains all
+  /// elements in [other].
+  ///
+  /// If [other] has multiple values that are equivalent according to
+  /// [equality], the first one reached during iteration takes precedence.
+  EqualitySet.from(Equality<E> equality, Iterable<E> other)
+      : super(new LinkedHashSet(
+            equals: equality.equals,
+            hashCode: equality.hash,
+            isValidKey: equality.isValidKey)) {
+    addAll(other);
+  }
+}