Fix various warnings and errors in html_diff and its annotations.

client/html/src/DocumentWrappingImplementation.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.
 
 class DocumentEventsImplementation extends ElementEventsImplementation
       implements DocumentEvents {
 
   DocumentEventsImplementation._wrap(_ptr) : super._wrap(_ptr);
 
   EventListenerList get readyStateChange() => _get('readystatechange');
@@ skipping 33 matching lines @@
 
   /** @domName cookie */
   String get cookie() => _documentPtr.cookie;
 
   /** @domName cookie */
   void set cookie(String value) { _documentPtr.cookie = value; }
 
   /** @domName defaultView */
   Window get window() => LevelDom.wrapWindow(_documentPtr.defaultView);
 
-  /** @domName designMode */
-  void set designMode(String value) { _documentPtr.dynamic.designMode = value; }
-
   /** @domName domain */
   String get domain() => _documentPtr.domain;
 
   /** @domName head */
   HeadElement get head() => LevelDom.wrapHeadElement(_documentPtr.head);
 
   /** @domName lastModified */
   String get lastModified() => _documentPtr.lastModified;
 
   /** @domName readyState */
@@ skipping 78 matching lines @@
   /** @domName HTMLHtmlElement.manifest */
   void set manifest(String value) { _ptr.manifest = value; }
 
   DocumentEvents get on() {
     if (_on === null) {
       _on = new DocumentEventsImplementation._wrap(_ptr);
     }
     return _on;
   }
 }