Reduce usage of ItearbleMixinWorkaround.

sdk/lib/collection/linked_hash_set.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;
 
-class LinkedHashSet<E> extends Collection<E> implements Set<E> {
+class LinkedHashSet<E> extends Collection<E> with _SetMixin<E>
+                       implements Set<E> {
   static const int _INITIAL_CAPACITY = 8;
   _LinkedHashTable<E> _table;
 
   LinkedHashSet() : _table = new _LinkedHashTable(_INITIAL_CAPACITY) {
     _table._container = this;
   }
 
   factory LinkedHashSet.from(Iterable<E> iterable) {
     return new LinkedHashSet<E>()..addAll(iterable);
   }
@@ skipping 68 matching lines @@
     return false;
   }
 
   void removeAll(Iterable objectsToRemove) {
     for (Object object in objectsToRemove) {
       _table._remove(object);
       _table._checkCapacity();
     }
   }
 
-  void retainAll(Iterable objectsToRemove) {
-    IterableMixinWorkaround.retainAll(this, objectsToRemove);
-  }
-
   void _filterWhere(bool test(E element), bool removeMatching) {
     int entrySize = _table._entrySize;
     int length = _table._table.length;
     int offset = _table._next(_LinkedHashTable._HEAD_OFFSET);
     while (offset != _LinkedHashTable._HEAD_OFFSET) {
       E key = _table._key(offset);
       int nextOffset = _table._next(offset);
       int modificationCount = _table._modificationCount;
       bool shouldRemove = (removeMatching == test(key));
       _table._checkModification(modificationCount);
@@ skipping 10 matching lines @@
   }
 
   void retainWhere(bool test(E element)) {
     _filterWhere(test, false);
   }
 
   void clear() {
     _table._clear();
   }
 
-  // Set.
-  bool isSubsetOf(Collection<E> other) {
-    // Deprecated, and using old signature.
-    Set otherSet;
-    if (other is Set) {
-      otherSet = other;
-    } else {
-      otherSet = other.toSet();
-    }
-    return IterableMixinWorkaround.setContainsAll(otherSet, this);
-  }
-
-  bool containsAll(Iterable<E> other) {
-    return IterableMixinWorkaround.setContainsAll(this, other);
-  }
-
-  Set<E> intersection(Set<E> other) {
-    return IterableMixinWorkaround.setIntersection(
-        this, other, new LinkedHashSet<E>());
-  }
-
-  Set<E> union(Set<E> other) {
-    return IterableMixinWorkaround.setUnion(
-        this, other, new LinkedHashSet<E>());
-  }
-
-  Set<E> difference(Set<E> other) {
-    return IterableMixinWorkaround.setDifference(
-        this, other, new LinkedHashSet<E>());
-  }
+  // Set interface from _SetMixin<E>.
+  Set<E> _newSet() => new LinkedHashSet<E>();
 
   String toString() => Collections.collectionToString(this);
 }