Roll Observatory packages and add a roll script

quiver/lib/src/collection/delegates/set.dart

-// Copyright 2013 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-part of quiver.collection;
-
-/**
- * An implementation of [Set] that delegates all methods to another [Set].
- * For instance you can create a FruitSet like this :
- *
- *     class FruitSet extends DelegatingSet<Fruit> {
- *       final Set<Fruit> _fruits = new Set<Fruit>();
- *
- *       Set<Fruit> get delegate => _fruits;
- *
- *       // custom methods
- *     }
- */
-abstract class DelegatingSet<E> extends DelegatingIterable<E>
-    implements Set<E> {
-  Set<E> get delegate;
-
-  bool add(E value) => delegate.add(value);
-
-  void addAll(Iterable<E> elements) => delegate.addAll(elements);
-
-  void clear() => delegate.clear();
-
-  bool containsAll(Iterable<Object> other) => delegate.containsAll(other);
-
-  Set<E> difference(Set<E> other) => delegate.difference(other);
-
-  Set<E> intersection(Set<Object> other) => delegate.intersection(other);
-
-  E lookup(Object object) => delegate.lookup(object);
-
-  bool remove(Object value) => delegate.remove(value);
-
-  void removeAll(Iterable<Object> elements) => delegate.removeAll(elements);
-
-  void removeWhere(bool test(E element)) => delegate.removeWhere(test);
-
-  void retainAll(Iterable<Object> elements) => delegate.retainAll(elements);
-
-  void retainWhere(bool test(E element)) => delegate.retainWhere(test);
-
-  Set<E> union(Set<E> other) => delegate.union(other);
-}