unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/lib/collection/collections.dart

-// Copyright (c) 2013, 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.
-
-part of dart.collection;
-
-/**
- * An unmodifiable [List] view of another List.
- *
- * The source of the elements may be a [List] or any [Iterable] with
- * efficient [Iterable.length] and [Iterable.elementAt].
- */
-class UnmodifiableListView<E> extends UnmodifiableListBase<E> {
-  final Iterable<E> _source;
-
-  /**
-   * Creates an unmodifiable list backed by [source].
-   *
-   * The [source] of the elements may be a [List] or any [Iterable] with
-   * efficient [Iterable.length] and [Iterable.elementAt].
-   */
-  UnmodifiableListView(Iterable<E> source) : _source = source;
-  int get length => _source.length;
-  E operator[](int index) => _source.elementAt(index);
-}