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

lib/web_ui.dart

Index: lib/web_ui.dart
diff --git a/lib/web_ui.dart b/lib/web_ui.dart
index b3ce998788a76eadd272546616d363012f4d157e..b7d6a37652981e0b42b4037e00f9fc3bbbea428c 100644
--- a/lib/web_ui.dart
+++ b/lib/web_ui.dart
@@ -617,9 +617,9 @@ abstract class WebComponent implements Element {
 
   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;