Refactor layout/relayout into a single method.

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 'dart:async';
 import 'dart:collection';
 import 'dart:mirrors';
 import 'dart:sky' as sky;
@@ skipping 546 matching lines @@
     List<UINode> children
   }) : super(
     key: key,
     children: children
   );
 }
 
 class FlexContainer extends OneChildListRenderNodeWrapper {
 
   RenderFlex root;
-  RenderFlex createNode() => new RenderFlex(this, this.direction);
+  RenderFlex createNode() => new RenderFlex(direction: this.direction);
 
   static final FlexContainer _emptyContainer = new FlexContainer();
     // direction doesn't matter if it's empty
 
   RenderNodeWrapper get emptyNode => _emptyContainer;
 
   final FlexDirection direction;
 
   FlexContainer({
     Object key,
@@ skipping 373 matching lines @@
                                           this.desiredWidth: double.INFINITY })
       : backgroundColor = backgroundColor,
         super(new BoxDecoration(backgroundColor: backgroundColor));
 
   BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
     return new BoxDimensions.withConstraints(constraints,
                                              height: desiredHeight,
                                              width: desiredWidth);
   }
 
-  void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
+  void performLayout() {
     width = constraints.constrainWidth(desiredWidth);
     height = constraints.constrainHeight(desiredHeight);
-    layoutDone();
   }
 
   void handlePointer(sky.PointerEvent event) {
     if (event.type == 'pointerdown')
       decoration = new BoxDecoration(backgroundColor: 0xFFFF0000);
     else if (event.type == 'pointerup')
       decoration = new BoxDecoration(backgroundColor: backgroundColor);
   }
 }
 
 class Rectangle extends RenderNodeWrapper {
 
   Rectangle(this.color, {
     Object key
   }) : super(
     key: key
   );
 
   final int color;
 
   RenderSolidColor root;
   RenderSolidColor createNode() => new RenderSolidColor(color, desiredWidth: 40.0, desiredHeight: 130.0);
 
   static final Rectangle _emptyRectangle = new Rectangle(0);
   RenderNodeWrapper get emptyNode => _emptyRectangle;
 
 }