Add an example of an app that manipulates both a RenderObject tree and has some fn logic in it.

Also:
 - Make RenderProxyBox non-abstract
 - Upgrade the old container.dart example
 - Minor fixes to ui_mode.dart to make this work

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1183503003.

examples/stocks2/lib/stock_app.dart

@@ -16,6 +16,7 @@ import 'package:sky/framework/widgets/popup_menu.dart';
 import 'package:sky/framework/widgets/radio.dart';
 import 'package:sky/framework/widgets/scaffold.dart';
 import 'package:sky/framework/widgets/tool_bar.dart';
+import 'package:sky/framework/widgets/ui_node.dart';
 import 'package:sky/framework/widgets/wrappers.dart';
 
 import 'stock_data.dart';
@@ -213,7 +214,7 @@ class StocksApp extends App {
 void main() {
   print("starting stocks app!");
   App app = new StocksApp();
-  app.appView.onFrame = () {
+  UINodeAppView.appView.onFrame = () {
     // uncomment this for debugging:
     // app.appView.debugDumpRenderTree();
   };

examples/widgets/container.dart

@@ -5,51 +5,44 @@
 import 'dart:sky' as sky;
 
 import 'package:sky/framework/rendering/box.dart';
+import 'package:sky/framework/rendering/flex.dart';
 import 'package:sky/framework/widgets/ui_node.dart';
 import 'package:sky/framework/widgets/wrappers.dart';
 
-import '../lib/solid_color_box.dart';
+class Rectangle extends Component {
 
-class Rectangle extends RenderObjectWrapper {
-  RenderSolidColorBox root;
-  RenderSolidColorBox createNode() =>
-      new RenderSolidColorBox(color, desiredSize: new sky.Size(40.0, 130.0));
+  Rectangle(this.color, { Object key }) : super(key: key);
 
-  final int color;
+  final Color color;
+
+  UINode build() {
+    return new FlexExpandingChild(
+      new Container(
+        decoration: new BoxDecoration(backgroundColor: color)
+      )
+    );
+  }
 
-  Rectangle(this.color, { Object key }) : super(key: key);
 }
 
 class ContainerApp extends App {
   UINode build() {
-    return new EventListenerNode(
-      new Block([
+    return new Flex([
+        new Rectangle(const Color(0xFF00FFFF), key: 'a'),
         new Container(
           padding: new EdgeDims.all(10.0),
           margin: new EdgeDims.all(10.0),
-          height: 100.0,
-          decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFF00FF00)),
-          child: new Block([
-            new Container(
-              decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFFFFFF00)),
-              height: 20.0
-            ),
-            new Image(src: "https://www.dartlang.org/logos/dart-logo.png",
-              size: new sky.Size(300.0, 300.0),
-              key: 1
-            ),
-          ])),
-      ]),
-      onPointerDown: _handlePointerDown,
-      onGestureTap: _handleGestureTap);
-  }
-
-  void _handlePointerDown(sky.PointerEvent event) {
-    print("_handlePointerDown");
-  }
-
-  void _handleGestureTap(sky.GestureEvent event) {
-    print("_handleGestureTap");
+          decoration: new BoxDecoration(backgroundColor: const Color(0xFFCCCCCC)),
+          child: new Image(src: "https://www.dartlang.org/logos/dart-logo.png",
+            size: new Size(300.0, 300.0),
+            key: 1
+          )
+        ),
+        new Rectangle(const Color(0xFFFFFF00), key: 'b'),
+      ],
+      direction: FlexDirection.vertical,
+      justifyContent: FlexJustifyContent.spaceBetween
+    );
   }
 }
 

examples/widgets/spinning_mixed.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:sky' as sky;
+
+import 'package:sky/framework/rendering/box.dart';
+import 'package:sky/framework/rendering/flex.dart';
+import 'package:sky/framework/scheduler.dart';
+import 'package:sky/framework/widgets/ui_node.dart';
+import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:vector_math/vector_math.dart';
+
+import '../lib/solid_color_box.dart';
+
+// Solid colour, RenderObject version
+void addFlexChildSolidColor(RenderFlex parent, sky.Color backgroundColor, { int flex: 0 }) {
+  RenderSolidColorBox child = new RenderSolidColorBox(backgroundColor);
+  parent.add(child);
+  child.parentData.flex = flex;
+}
+
+// Solid colour, Widget version
+class Rectangle extends Component {
+  Rectangle(this.color, { Object key }) : super(key: key);
+  final Color color;
+  UINode build() {
+    return new FlexExpandingChild(
+      new Container(
+        decoration: new BoxDecoration(backgroundColor: color)
+      )
+    );
+  }
+}
+
+UINode builder() {
+  return new Flex([
+      new Rectangle(const Color(0xFF00FFFF), key: 'a'),
+      new Container(
+        padding: new EdgeDims.all(10.0),
+        margin: new EdgeDims.all(10.0),
+        decoration: new BoxDecoration(backgroundColor: const Color(0xFFCCCCCC)),
+        child: new Image(src: "https://www.dartlang.org/logos/dart-logo.png",
+          size: new Size(300.0, 300.0),
+          key: 1
+        )
+      ),
+      new Rectangle(const Color(0xFFFFFF00), key: 'b'),
+    ],
+    direction: FlexDirection.vertical,
+    justifyContent: FlexJustifyContent.spaceBetween
+  );
+}
+
+double timeBase;
+RenderTransform transformBox;
+
+void rotate(double timeStamp) {
+  if (timeBase == null)
+    timeBase = timeStamp;
+  double delta = (timeStamp - timeBase) / 1000; // radians
+
+  transformBox.setIdentity();
+  transformBox.translate(transformBox.size.width / 2.0, transformBox.size.height / 2.0);
+  transformBox.rotateZ(delta);
+  transformBox.translate(-transformBox.size.width / 2.0, -transformBox.size.height / 2.0);
+}
+
+void main() {
+  RenderFlex flexRoot = new RenderFlex(direction: FlexDirection.vertical);
+
+  RenderProxyBox proxy = new RenderProxyBox();
+  new RenderObjectToUINodeAdapter(proxy, builder); // adds itself to proxy
+
+  addFlexChildSolidColor(flexRoot, const sky.Color(0xFFFF00FF), flex: 1);
+  flexRoot.add(proxy);
+  addFlexChildSolidColor(flexRoot, const sky.Color(0xFF0000FF), flex: 1);
+
+  transformBox = new RenderTransform(child: flexRoot, transform: new Matrix4.identity());
+  RenderPadding root = new RenderPadding(padding: new EdgeDims.all(20.0), child: transformBox);
+
+  // Because we're going to use UINodes, we want to initialise its
+  // AppView, not use the default one. We don't really need to do
+  // this, because RenderObjectToUINodeAdapter does it for us, but
+  // it's good practice in case we happen to not have a
+  // RenderObjectToUINodeAdapter in our tree at startup.
+  UINodeAppView.initUINodeAppView();
+  UINodeAppView.appView.root = root;
+
+  addPersistentFrameCallback(rotate);
+}

sdk/lib/framework/rendering/box.dart

@@ -248,8 +248,9 @@ abstract class RenderBox extends RenderObject {
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}size: ${size}\n';
 }
 
-abstract class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
-  RenderProxyBox(RenderBox child) {
+class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
+
+  RenderProxyBox([RenderBox child = null]) {
     this.child = child;
   }
 
@@ -297,6 +298,7 @@ abstract class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<
     if (child != null)
       child.paint(canvas);
   }
+
 }
 
 class RenderSizedBox extends RenderProxyBox {

sdk/lib/framework/widgets/ui_node.dart

@@ -28,7 +28,7 @@ abstract class UINode {
 
   UINode({ Object key }) {
     _key = key == null ? "$runtimeType" : "$runtimeType-$key";
-    assert(this is App || _inRenderDirtyComponents); // you should not build the UI tree ahead of time, build it only during build()
+    assert(this is AbstractUINodeRoot || _inRenderDirtyComponents); // you should not build the UI tree ahead of time, build it only during build()
   }
 
   String _key;
@@ -752,6 +752,7 @@ class UINodeAppView extends AppView {
   }
 
   static UINodeAppView _appView;
+  static AppView get appView => _appView;
   static void initUINodeAppView() {
     if (_appView == null)
       _appView = new UINodeAppView();
@@ -801,8 +802,6 @@ abstract class App extends AbstractUINodeRoot {
 
   App();
 
-  AppView get appView => UINodeAppView._appView;
-
   void _buildIfDirty() {
     super._buildIfDirty();