Deprecate Set.isSubsetOf, make Set.containsAll accept iterable.

sdk/lib/core/set.dart

 // Copyright (c) 2011, 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.core;
 
 /**
  * This class is the public interface of a set. A set is a collection
  * without duplicates.
  */
@@ skipping 18 matching lines @@
 
   /**
    * Removes [value] from the set. Returns true if [value] was
    * in the set. Returns false otherwise. The method has no effect
    * if [value] value was not in the set.
    */
   bool remove(Object value);
 
   /**
    * Returns true if [other] contains all the elements of this Set.
+   *
+   * *Deprecated*. Use `other.containsAll(thisSet)` instead if [other]
+   * is a Set, and convert `other` to a Set if it isn't.
    */
-  bool isSubsetOf(Set<E> other);
+  @deprecated
+  bool isSubsetOf(Iterable<E> other);
 
   /**
    * Returns true if this Set contains all the elements of [other].
    */
-  bool containsAll(Set<E> other);
+  bool containsAll(Iterable<E> other);
 
   /**
    * Returns a new set which is the intersection between this set and [other].
    */
   Set<E> intersection(Set<E> other);
 
   /**
    * Returns a new set which contains all the elements of this set and [other].
    */
   Set<E> union(Set<E> other);
 
   /**
    * Returns a new set with the the elements of this that are not in [other].
    */
   Set<E> difference(Set<E> other);
 
   /**
    * Removes all elements in the set.
    */
   void clear();
 }