Don't use file-based part-of when part files are shared.

sdk/lib/html/html_common/lists.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 "html_common.dart";
+part of html_common;
 
 class Lists {
   /**
    * Returns the index in the array [a] of the given [element], starting
    * the search at index [startIndex] to [endIndex] (exclusive).
    * Returns -1 if [element] is not found.
    */
   static int indexOf(List a, Object element, int startIndex, int endIndex) {
     if (startIndex >= a.length) {
       return -1;
@@ skipping 46 matching lines @@
     return accumulator;
   }
 }
 
 /**
  * For accessing underlying node lists, for dart:js interop.
  */
 abstract class NodeListWrapper {
   List<Node> get rawList;
 }