Port DrawerHeader to fn2 world.

sky/sdk/lib/framework/fn2.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 'app.dart';
 import 'dart:async';
 import 'dart:collection';
 import 'dart:mirrors';
@@ skipping 389 matching lines @@
   void syncRenderObject(DecoratedBox old) {
     super.syncRenderObject(old);
     root.decoration = decoration;
   }
 }
 
 class SizedBox extends OneChildRenderObjectWrapper {
   RenderSizedBox root;
   final Size desiredSize;
 
-  SizedBox({ this.desiredSize, UINode child, Object key })
-    : super(child: child, key: key);
+  SizedBox({
+    this.desiredSize: sky.Size.infinite,

[eseidel, 2015/06/08 17:55:21]

sky.

+    UINode child,
+    Object key
+  }) : super(child: child, key: key);
 
   RenderSizedBox createNode() => new RenderSizedBox(desiredSize: desiredSize);
 
   void syncRenderObject(SizedBox old) {
     super.syncRenderObject(old);
     root.desiredSize = desiredSize;
   }
 }
 
 class Transform extends OneChildRenderObjectWrapper {
@@ skipping 537 matching lines @@
 
     if (desiredSize != null)
       current = new SizedBox(desiredSize: desiredSize, child: current);
 
     if (margin != null)
       current = new Padding(padding: margin, child: current);
 
     if (transform != null)
       current = new Transform(transform: transform, child: current);
 
+    if (current == null)
+      current = new SizedBox();

[eseidel, 2015/06/08 17:55:21]

What is a sized box with no size?  0x0?

+
     return current;
   }
 }
 
 class _AppView extends AppView {
   _AppView() : super(null);
 
   void dispatchEvent(sky.Event event, HitTestResult result) {
     super.dispatchEvent(event, result);
 
@@ skipping 28 matching lines @@
     assert(root.parent is RenderView);
   }
 }
 
 class Text extends Component {
   Text(this.data) : super(key: '*text*');
   final String data;
   bool get interchangeable => true;
   UINode build() => new Paragraph(text: data);
 }