Make List.skip, List.take and List.reversed return Iterables, not Lists.

tools/dom/templates/html/impl/impl_Node.darttemplate

 // Copyright (c) 2012, 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 $LIBRARYNAME;
 
 /**
  * Lazy implementation of the child nodes of an element that does not request
  * the actual child nodes of an element until strictly necessary greatly
  * improving performance for the typical cases where it is not required.
@@ skipping 179 matching lines @@
   }
 
   Node singleMatching(bool test(Node value)) {
     return IterableMixinWorkaround.singleMatching(this, test);
   }
 
   Node elementAt(int index) {
     return this[index];
   }
 
-  List<Node> get reversed {
+  Iterable<Node> get reversed {
     return IterableMixinWorkaround.reversedList(this);
   }
 
   // TODO(jacobr): this could be implemented for child node lists.
   // The exception we throw here is misleading.
   void sort([int compare(Node a, Node b)]) {
     throw new UnsupportedError("Cannot sort immutable List.");
   }
 
   int indexOf(Node element, [int start = 0]) =>
@@ skipping 69 matching lines @@
       final Node parent = this.parentNode;
       parent.$dom_replaceChild(otherNode, this);
     } catch (e) {
 
     };
     return this;
   }
 
 $!MEMBERS
 }