Make sure that classes in dart:html do not implement both List and List<E>.

tools/dom/templates/html/impl/impl_Element.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;
 
 class _ChildrenElementList extends ListBase<Element>
     implements NodeListWrapper {
   // Raw Element.
   final Element _element;
@@ skipping 241 matching lines @@
   @Experimental()
   CssRect get marginEdge;
 $!STREAM_GETTER_SIGNATURES
 }
 
 // TODO(jacobr): this is an inefficient implementation but it is hard to see
 // a better option given that we cannot quite force NodeList to be an
 // ElementList as there are valid cases where a NodeList JavaScript object
 // contains Node objects that are not Elements.
 class _FrozenElementList<T extends Element> extends ListBase<T>
-    implements ElementList, NodeListWrapper {
+    implements ElementList<T>, NodeListWrapper {
   final List<Node> _nodeList;
   // The subset of _nodeList that are Elements.
   List<Element> _elementList;
 
   _FrozenElementList._wrap(this._nodeList) {
     _elementList = _nodeList.where((e) => e is Element).toList();
   }
 
   int get length => _nodeList.length;
 
@@ skipping 1016 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }