Port first sector demo to fn3

Also, fix warnings in rendering/sector_layout.dart
Also, fix hit testing in rendering/sector_layout.dart
Also, add WidgetToRenderBoxAdapter
Also, make the rendering library debugging tools more resilient to
dumping stuff before layout is complete.

examples/raw/pubspec.yaml

-name: raw
+name: sky_raw_examples
 dependencies:
   flutter: ">=0.0.3 <0.1.0"
   sky_tools: any

examples/rendering/pubspec.yaml

-name: rendering
+name: flutter_rendering_examples
 dependencies:
   flutter: ">=0.0.3 <0.1.0"
   sky_tools: any

examples/widgets/pubspec.yaml

-name: widgets
+name: sky_widgets_examples
 dependencies:
   flutter: ">=0.0.3 <0.1.0"
   sky_tools: any
+  flutter_rendering_examples: any
 dependency_overrides:
   material_design_icons:
     path: ../../sky/packages/material_design_icons
   flutter:
     path: ../../sky/packages/sky
+  flutter_rendering_examples:
+    path: ../rendering

examples/widgets/sector.dart.old → examples/widgets/sector.dart

@@ -7,7 +7,7 @@ import 'dart:math' as math;
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 
-import '../rendering/sector_layout.dart';
+import 'package:flutter_rendering_examples/sector_layout.dart';
 
 RenderBox initCircle() {
   return new RenderBoxToRenderSectorAdapter(
@@ -16,10 +16,14 @@ RenderBox initCircle() {
   );
 }
 
-class SectorApp extends MaterialApp {
+class SectorApp extends StatefulComponent {
+  SectorAppState createState() => new SectorAppState();
+}
+
+class SectorAppState extends State<SectorApp> {
 
-  RenderBoxToRenderSectorAdapter sectors = initCircle();
-  math.Random rand = new math.Random(1);
+  final RenderBoxToRenderSectorAdapter sectors = initCircle();
+  final math.Random rand = new math.Random(1);
 
   void addSector() {
     double deltaTheta;
@@ -52,27 +56,27 @@ class SectorApp extends MaterialApp {
   RenderBoxToRenderSectorAdapter sectorAddIcon = initSector(const Color(0xFF00DD00));
   RenderBoxToRenderSectorAdapter sectorRemoveIcon = initSector(const Color(0xFFDD0000));
 
-  bool enabledAdd = true;
-  bool enabledRemove = false;
+  bool _enabledAdd = true;
+  bool _enabledRemove = false;
   void updateEnabledState() {
     setState(() {
       var ring = (sectors.child as RenderSectorRing);
       SectorDimensions currentSize = ring.getIntrinsicDimensions(const SectorConstraints(), ring.deltaRadius);
-      enabledAdd = currentSize.deltaTheta < kTwoPi;
-      enabledRemove = ring.firstChild != null;
+      _enabledAdd = currentSize.deltaTheta < kTwoPi;
+      _enabledRemove = ring.firstChild != null;
     });
   }
 
   Widget buildBody() {
     return new Material(
-      child: new Column([
+      child: new Column(<Widget>[
           new Container(
             padding: new EdgeDims.symmetric(horizontal: 8.0, vertical: 25.0),
-            child: new Row([
+            child: new Row(<Widget>[
                 new RaisedButton(
-                  enabled: enabledAdd,
+                  enabled: _enabledAdd,
                   child: new IntrinsicWidth(
-                    child: new Row([
+                    child: new Row(<Widget>[
                       new Container(
                         padding: new EdgeDims.all(4.0),
                         margin: new EdgeDims.only(right: 10.0),
@@ -84,9 +88,9 @@ class SectorApp extends MaterialApp {
                   onPressed: addSector
                 ),
                 new RaisedButton(
-                  enabled: enabledRemove,
+                  enabled: _enabledRemove,
                   child: new IntrinsicWidth(
-                    child: new Row([
+                    child: new Row(<Widget>[
                       new Container(
                         padding: new EdgeDims.all(4.0),
                         margin: new EdgeDims.only(right: 10.0),
@@ -117,18 +121,20 @@ class SectorApp extends MaterialApp {
     );
   }
 
-  Widget build() {
-    return new Theme(
-      data: new ThemeData.light(),
-      child: new Title(
-        title: 'Sector Layout',
-        child: new Scaffold(
-          toolBar: new ToolBar(
-            center: new Text('Sector Layout in a Widget Tree')
-          ),
-          body: buildBody()
-        )
-      )
+  Widget build(BuildContext context) {
+    return new MaterialApp(
+      theme: new ThemeData.light(),
+      title: 'Sector Layout',
+      routes: <String, RouteBuilder>{
+        '/': (RouteArguments args) {
+          return new Scaffold(
+            toolBar: new ToolBar(
+              center: new Text('Sector Layout in a Widget Tree')
+            ),
+            body: buildBody()
+          );
+        }
+      }
     );
   }
 }

packages/flutter/lib/src/rendering/box.dart

@@ -633,7 +633,7 @@ abstract class RenderBox extends RenderObject {
     }
   }
 
-  String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}size: $size\n';
+  String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}size: ${ hasSize ? size : "MISSING" }\n';
 }
 
 /// A mixin that provides useful default behaviors for boxes with children

packages/flutter/lib/src/widgets/basic.dart

@@ -961,6 +961,22 @@ class AssetImage extends StatelessComponent {
   }
 }
 
+class WidgetToRenderBoxAdapter extends LeafRenderObjectWidget {
+  WidgetToRenderBoxAdapter(RenderBox renderBox)
+    : renderBox = renderBox,
+      // WidgetToRenderBoxAdapter objects are keyed to their render box. This
+      // prevents the widget being used in the widget hierarchy in two different
+      // places, which would cause the RenderBox to get inserted in multiple
+      // places in the RenderObject tree.
+      super(key: new GlobalObjectKey(renderBox)) {
+    assert(renderBox != null);
+  }
+
+  final RenderBox renderBox;
+
+  RenderBox createRenderObject() => renderBox;
+}
+
 
 // EVENT HANDLING