Replace BoxDimensions with sky.Size

sky/examples/raw/render_paragraph.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';
 import 'package:sky/framework/app.dart';
 import 'package:sky/framework/layout2.dart';
 
 class RenderSolidColor extends RenderDecoratedBox {
   final double desiredHeight;
   final double desiredWidth;
   final int backgroundColor;
 
   RenderSolidColor(int backgroundColor, { this.desiredHeight: double.INFINITY,
                                           this.desiredWidth: double.INFINITY })
       : backgroundColor = backgroundColor,
         super(new BoxDecoration(backgroundColor: backgroundColor));
 
-  BoxDimensions getIntrinsicDimensions(BoxConstraints constraints) {
-    return new BoxDimensions.withConstraints(constraints,
-                                             height: desiredHeight,
-                                             width: desiredWidth);
+  Size getIntrinsicDimensions(BoxConstraints constraints) {
+    return constraints.constrain(new Size(desiredWidth, desiredHeight));
   }
 
   void performLayout() {
     width = constraints.constrainWidth(desiredWidth);
     height = constraints.constrainHeight(desiredHeight);
   }
 
   void handlePointer(PointerEvent event) {
     if (event.type == 'pointerdown')
       decoration = new BoxDecoration(backgroundColor: 0xFFFF0000);
@@ skipping 19 matching lines @@
 andouille leberkas capicola meatloaf. Chicken pig ball tip pork picanha bresaola
 alcatra. Pork pork belly alcatra, flank chuck drumstick biltong doner jowl.
 Pancetta meatball tongue tenderloin rump tail jowl boudin.""";
 
   child = new RenderParagraph(meatyString);
   root.add(child);
   child.parentData.flex = 1;
 
   app = new AppView(root);
 }