Fix theme changing: turns out we were not reparenting stateful surviving nodes when their parents c…

sky/sdk/lib/widgets/widget.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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:mirrors';
 import 'dart:sky' as sky;
 
 import '../base/hit_test.dart';
@@ skipping 32 matching lines @@
   Widget get parent => _parent;
 
   bool _mounted = false;
   bool _wasMounted = false;
   bool get mounted => _mounted;
   static bool _notifyingMountStatus = false;
   static List<Widget> _mountedChanged = new List<Widget>();
 
   void setParent(Widget newParent) {
     assert(!_notifyingMountStatus);
+    if (_parent == newParent)
+      return;
     _parent = newParent;
     if (newParent == null) {
       if (_mounted) {
         _mounted = false;
         _mountedChanged.add(this);
       }
     } else {
       assert(newParent._mounted);
       if (_parent._mounted != _mounted) {
         _mounted = _parent._mounted;
@@ skipping 76 matching lines @@
       removeChild(oldNode);
       assert(!oldNode.mounted);
       return null;
     }
 
     if (oldNode != null) {
       if (oldNode.runtimeType == node.runtimeType && oldNode.key == node.key) {
         if (node._retainStatefulNodeIfPossible(oldNode)) {
           assert(oldNode.mounted);
           assert(!node.mounted);
+          oldNode.setParent(this);
           oldNode._sync(node, slot);
           assert(oldNode.root is RenderObject);
           return oldNode;
         }
       } else {
         assert(oldNode.mounted);
         oldNode.detachRoot();
         removeChild(oldNode);
         oldNode = null;
       }
@@ skipping 791 matching lines @@
 }
 
 class AppContainer extends AbstractWidgetRoot {
   AppContainer(this.app) {
     assert(SkyBinding.instance is WidgetSkyBinding);
   }
   final App app;
   Widget build() => new RenderViewWrapper(child: app);
 }
 
-void runApp(App app, { RenderView renderViewOverride }) {
+void runApp(App app, { RenderView renderViewOverride, bool enableProfilingLoop: false }) {
   WidgetSkyBinding.initWidgetSkyBinding(renderViewOverride: renderViewOverride);
   new AppContainer(app);
+  if (enableProfilingLoop) {
+    new Timer.periodic(const Duration(milliseconds: 20), (_) {
+      app.scheduleBuild();
+    });
+  }
 }
 
 typedef Widget Builder();
 
 class RenderBoxToWidgetAdapter extends AbstractWidgetRoot {
 
   RenderBoxToWidgetAdapter(
     RenderObjectWithChildMixin<RenderBox> container,
     this.builder
   ) : _container = container, super() {
@@ skipping 24 matching lines @@
     if (root.parent == null) {
       // we haven't attached it yet
       assert(_container.child == null);
       _container.child = root;
     }
     assert(root.parent == _container);
   }
 
   Widget build() => builder();
 }