Load deferred chunks in the right order.

sdk/lib/async/deferred_load.dart

 // Copyright (c) 2013, 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.async;
 
 /**
  * Indicates that loading of [libraryName] is deferred.
  *
  * Applies to library imports, when used as metadata.
@@ skipping 16 matching lines @@
  */
 class DeferredLibrary {
   final String libraryName;
   final String uri;
 
   const DeferredLibrary(this.libraryName, {this.uri});
 
   /**
    * Ensure that [libraryName] has been loaded.
    *
-   * The value of the returned future is true if this invocation of
-   * [load] caused the library to be loaded.
-   *
    * If the library fails to load, the Future will complete with a
    * DeferredLoadException.
    */
-  external Future<bool> load();
+  external Future<Null> load();
 }
 
 /**
  * Thrown when a deferred library fails to load.
  */
 class DeferredLoadException implements Exception {
   DeferredLoadException(String this._s);
   String toString() => "DeferredLoadException: '$_s'";
   final String _s;
 }