Fix type errors detected with --error-on-bad-type.

runtime/lib/collection_patch.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.
 
 patch class HashMap<K, V> {
   /* patch */ factory HashMap({ bool equals(K key1, K key2),
                                 int hashCode(K key),
                                 bool isValidKey(potentialKey) }) {
     if (isValidKey == null) {
       if (hashCode == null) {
@@ skipping 827 matching lines @@
   bool contains(Object key) => _map.containsKey(key);
   bool get isEmpty => _map.isEmpty;
   bool get isNotEmpty => _map.isNotEmpty;
   int get length => _map.length;
 }
 
 class _LinkedHashMapValueIterable<V> extends IterableBase<V>
                                      implements EfficientLength {
   LinkedHashMap<dynamic, V> _map;
   _LinkedHashMapValueIterable(this._map);
-  Iterator<K> get iterator => new _LinkedHashMapValueIterator<V>(_map);
+  Iterator<V> get iterator => new _LinkedHashMapValueIterator<V>(_map);
   bool contains(Object value) => _map.containsValue(value);
   bool get isEmpty => _map.isEmpty;
   bool get isNotEmpty => _map.isNotEmpty;
   int get length => _map.length;
 }
 
 abstract class _LinkedHashMapIterator<T> implements Iterator<T> {
   final LinkedHashMap _map;
   var _next;
   T _current;
@@ skipping 394 matching lines @@
       return false;
     }
     _LinkedHashSetEntry entry = _next;
     _current = entry.key;
     _next = entry._nextEntry;
     return true;
   }
 
   E get current => _current;
 }