Revert all html warning changes.

pkg/custom_element/lib/custom_element.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.
 
 /**
  * Custom DOM elements.
  *
  * This library provides access to the Polymer project's
  * [Custom Elements]
  * (http://www.polymer-project.org/platform/custom-elements.html)
@@ skipping 231 matching lines @@
   void setInnerHtml(String html,
     {NodeValidator validator, NodeTreeSanitizer treeSanitizer}) {
     host.setInnerHtml(html, validator: validator, treeSanitizer: treeSanitizer);
   }
 
   DocumentFragment createFragment(String html,
       {NodeValidator validator, NodeTreeSanitizer treeSanitizer}) =>
     host.createFragment(html,
         validator: validator, treeSanitizer: treeSanitizer);
 
+  InputMethodContext get inputMethodContext => host.inputMethodContext;
+
   bool get isContentEditable => host.isContentEditable;
 
   String get lang => host.lang;
   set lang(String v) { host.lang = v; }
 
   String get outerHtml => host.outerHtml;
 
   bool get spellcheck => host.spellcheck;
   set spellcheck(bool v) { host.spellcheck = v; }
 
@@ skipping 233 matching lines @@
   Stream<TouchEvent> get onTouchLeave => host.onTouchLeave;
   Stream<TouchEvent> get onTouchMove => host.onTouchMove;
   Stream<TouchEvent> get onTouchStart => host.onTouchStart;
   Stream<TransitionEvent> get onTransitionEnd => host.onTransitionEnd;
 
   // TODO(sigmund): do the normal forwarding when dartbug.com/7919 is fixed.
   Stream<WheelEvent> get onMouseWheel {
     throw new UnsupportedError('onMouseWheel is not supported');
   }
 }