Update charted to 0.4.8 and roll

packages/collection/lib/src/combined_wrappers/combined_list.dart

+// Copyright (c) 2017, 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';
+
+/// A view of several lists combined into a single list.
+///
+/// All methods and accessors treat the [CombinedListView] list as if it were a
+/// single concatenated list, but the underlying implementation is based on
+/// lazily accessing individual list instances. This means that if the
+/// underlying lists change, the [CombinedListView] will reflect those changes.
+///
+/// The index operator (`[]`) and [length] property of a [CombinedListView] are
+/// both `O(lists)` rather than `O(1)`. A [CombinedListView] is unmodifiable.
+class CombinedListView<T> extends ListBase<T>
+    implements UnmodifiableListView<T> {
+  static void _throw() {
+    throw new UnsupportedError('Cannot modify an unmodifiable List');
+  }
+
+  /// The lists that this combines.
+  final List<List<T>> _lists;
+
+  /// Creates a combined view of [lists].
+  CombinedListView(this._lists);
+
+  set length(int length) {
+    _throw();
+  }
+
+  int get length => _lists.fold(0, (length, list) => length + list.length);
+
+  T operator [](int index) {
+    var initialIndex = index;
+    for (var i = 0; i < _lists.length; i++) {
+      var list = _lists[i];
+      if (index < list.length) {
+        return list[index];
+      }
+      index -= list.length;
+    }
+    throw new RangeError.index(initialIndex, this, 'index', null, length);
+  }
+
+  void operator []=(int index, T value) {
+    _throw();
+  }
+
+  void clear() {
+    _throw();
+  }
+
+  bool remove(Object element) {
+    _throw();
+    return null;
+  }
+
+  void removeWhere(bool filter(T element)) {
+    _throw();
+  }
+
+  void retainWhere(bool filter(T element)) {
+    _throw();
+  }
+}