Removing interfaces from dart:html

lib/html/templates/html/interface/interface_NodeList.darttemplate

 // 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.
 
 // WARNING: Do not edit - generated code.
 
 $!COMMENT
-interface $ID$EXTENDS {
+abstract class $ID$EXTENDS {
 
   NodeList filter(bool f(Node element));
 
   NodeList getRange(int start, int length);
 
   Node get first;
 
 $!MEMBERS
 }