[Effen] Now that we have RenderNode.parent again, we can have mid-tree sync() work properly again.

sky/sdk/lib/framework/fn.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 library fn;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:sky' as sky;
 import 'reflect.dart' as reflect;
@@ skipping 868 matching lines @@
     _dirty = false;
     _root = _built._root;
     assert(_root != null);
   }
 
   void _buildIfDirty() {
     if (!_dirty || _defunct)
       return;
 
     _trace('$_key rebuilding...');
-    _sync(null, null, null); // TODO(ianh): figure out how passing "null, null, null" here is ok
+    _sync(null, _root.parent, _root.parent.childAfter(_root));
   }
 
   void scheduleBuild() {
     setState(() {});
   }
 
   void setState(Function fn()) {
     _stateful = true;
     fn();
     if (_isBuilding || _dirty || _defunct)
@@ skipping 22 matching lines @@
     _sync(null, _host, _root);
   }
 }
 
 class Text extends Component {
   Text(this.data) : super(key: '*text*');
   final String data;
   bool get interchangeable => true;
   UINode build() => new Paragraph(children: [new TextFragment(data)]);
 }