Update charted to 0.4.8 and roll

packages/quiver/lib/src/iterables/cycle.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.iterables;
 
-/**
- * Returns an [Iterable] that infinitely cycles through the elements of
- * [iterable]. If [iterable] is empty, the returned Iterable will also be empty.
- */
-Iterable cycle(Iterable iterable) => new _Cycle(iterable);
+/// Returns an [Iterable] that infinitely cycles through the elements of
+/// [iterable]. If [iterable] is empty, the returned Iterable will also be empty.
+Iterable<T> cycle<T>(Iterable<T> iterable) => new _Cycle<T>(iterable);
 
 class _Cycle<T> extends InfiniteIterable<T> {
   final Iterable<T> _iterable;
 
   _Cycle(this._iterable);
 
   Iterator<T> get iterator => new _CycleIterator(_iterable);
 
   bool get isEmpty => _iterable.isEmpty;
 
   bool get isNotEmpty => _iterable.isNotEmpty;
 
   // TODO(justin): add methods that can be answered by the wrapped iterable
 }
 
 class _CycleIterator<T> implements Iterator<T> {
   final Iterable<T> _iterable;
   Iterator<T> _iterator;
 
-  _CycleIterator(_iterable)
+  _CycleIterator(Iterable<T> _iterable)
       : _iterable = _iterable,
         _iterator = _iterable.iterator;
 
   T get current => _iterator.current;
 
   bool moveNext() {
     if (!_iterator.moveNext()) {
       _iterator = _iterable.iterator;
       return _iterator.moveNext();
     }
     return true;
   }
 }