Don't put private members in dart:html interfaces.

client/html/generated/html/dartium/Node.dart

Index: client/html/generated/html/dartium/Node.dart
diff --git a/client/html/generated/html/dartium/Node.dart b/client/html/generated/html/dartium/Node.dart
index 55cd4f939918ae7c02f1c6c85efa863b231b5767..8fa3c4fa344615cca701d7aee4f423ba69b64c4b 100644
--- a/client/html/generated/html/dartium/Node.dart
+++ b/client/html/generated/html/dartium/Node.dart
@@ -22,14 +22,16 @@ class _NodeImpl extends _EventTargetImpl implements Node {
   // TODO(jacobr): should we throw an exception if parent is already null?
   _NodeImpl remove() {
     if (this.parent != null) {
-      this.parent._removeChild(this);
+      final _NodeImpl parent = this.parent;
+      parent._removeChild(this);
     }
     return this;
   }
 
   _NodeImpl replaceWith(Node otherNode) {
     try {
-      this.parent._replaceChild(otherNode, this);
+      final _NodeImpl parent = this.parent;
+      parent._replaceChild(otherNode, this);
     } catch(var e) {
       
     };