Address comments directly in master, adjust for new sdk html fields.

lib/web_ui.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This library exports all of the commonly used functions and types for
  * building UI's. It is equivalent to the following imports:
  *
  *     import 'package:web_ui/observe.dart';
  *     import 'package:web_ui/safe_html.dart';
@@ skipping 599 matching lines @@
   void $dom_removeAttribute(String name) =>
       host.$dom_removeAttribute(name);
 
   void $dom_setAttribute(String name, String value) =>
       host.$dom_setAttribute(name, value);
 
   get $dom_attributes => host.$dom_attributes;
 
   List<Node> get $dom_childNodes => host.$dom_childNodes;
 
-  Node get $dom_firstChild => host.$dom_firstChild;
+  Node get firstChild => host.firstChild;
 
-  Node get $dom_lastChild => host.$dom_lastChild;
+  Node get lastChild => host.lastChild;
 
   String get localName => host.localName;
   String get $dom_localName => host.$dom_localName;
 
   String get namespaceUri => host.namespaceUri;
   String get $dom_namespaceUri => host.$dom_namespaceUri;
 
   int get nodeType => host.nodeType;
 
   void $dom_addEventListener(String type, EventListener listener,
@@ skipping 125 matching lines @@
 }
 
 /**
  * Set this to true to use native Shadow DOM if it is supported.
  * Note that this will change behavior of [WebComponent] APIs for tree
  * traversal.
  */
 bool useShadowDom = false;
 
 bool get _realShadowRoot => useShadowDom && ShadowRoot.supported;