Settings menu item in stock2 doesn't work

sky/sdk/lib/widgets/widget.dart

Index: sky/sdk/lib/widgets/widget.dart
diff --git a/sky/sdk/lib/widgets/widget.dart b/sky/sdk/lib/widgets/widget.dart
index 7d450c98b11bdc330f7d7a1c48fb41004364fb4f..ed2e9cb5d4c67d9fb5da3c50dc7617c4752f512d 100644
--- a/sky/sdk/lib/widgets/widget.dart
+++ b/sky/sdk/lib/widgets/widget.dart
@@ -23,7 +23,7 @@ abstract class Widget {
 
   Widget({ String key }) {
     _key = key != null ? key : runtimeType.toString();
-    assert(this is AbstractWidgetRoot || _inRenderDirtyComponents); // you should not build the UI tree ahead of time, build it only during build()
+    assert(this is AbstractWidgetRoot || this is App || _inRenderDirtyComponents); // you should not build the UI tree ahead of time, build it only during build()
   }
 
   String _key;
@@ -474,7 +474,7 @@ abstract class RenderObjectWrapper extends Widget {
   static RenderObjectWrapper _getMounted(RenderObject node) => _nodeMap[node];
 
   void _sync(Widget old, dynamic slot) {
-    assert(parent != null);
+    assert(parent != null || this is RenderViewWrapper);

[Hixie, 2015/06/17 19:21:25]

This should never be called for RenderViewWrapper. It does tons of work that's
irrelevant for that class. We should just override it in RenderViewWrapper to do
the one line of code we care about (_root = createNode()), and in fact, maybe
should even fix that.

In fact, maybe we should refactor RenderObjectWrapper into two, so that
RenderViewWrapper can inherit from a version of it that doesn't use
createNode().

     if (old == null) {
       _root = createNode();
       var ancestor = findAncestor(RenderObjectWrapper);
@@ -767,10 +767,12 @@ class WidgetAppView extends AppView {
 
 }
 
+abstract class App extends Component {
+}
+
 abstract class AbstractWidgetRoot extends Component {
 
-  AbstractWidgetRoot({ RenderView renderViewOverride }) : super(stateful: true) {
-    WidgetAppView.initWidgetAppView(renderViewOverride: renderViewOverride);
+  AbstractWidgetRoot() : super(stateful: true) {
     _mounted = true;
     _scheduleComponentForRender(this);
   }
@@ -789,20 +791,21 @@ abstract class AbstractWidgetRoot extends Component {
 
 }
 
-abstract class App extends AbstractWidgetRoot {
-
-  App({ RenderView renderViewOverride }) : super(renderViewOverride: renderViewOverride);
-
-  void _buildIfDirty() {
-    super._buildIfDirty();
+class RenderViewWrapper extends OneChildRenderObjectWrapper {
+  RenderViewWrapper({ String key, Widget child }) : super(key: key, child: child);
+  RenderView get root => super.root;
+  RenderView createNode() => WidgetAppView._appView.renderView;
+}
 
-    if (root.parent == null) {
-      // we haven't attached it yet
-      WidgetAppView._appView.root = root;
-    }
-    assert(root.parent is RenderView);
-  }
+class AppContainer extends AbstractWidgetRoot {
+  AppContainer(this.app);
+  final App app;
+  Widget build() => new RenderViewWrapper(child: app);
+}
 
+void runApp(App app, { RenderView renderViewOverride }) {
+  WidgetAppView.initWidgetAppView(renderViewOverride: renderViewOverride);
+  new AppContainer(app);
 }
 
 typedef Widget Builder();