Let's hide double.INFINITY a bit more, by providing cleaner APIs for the cases where we're currentl…

sky/sdk/lib/widgets/basic.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:vector_math/vector_math.dart';
 
 import '../painting/text_style.dart';
 import '../rendering/block.dart';
@@ skipping 272 matching lines @@
   final EdgeDims margin;
   final EdgeDims padding;
   final Matrix4 transform;
   final double width;
   final double height;
 
   Widget build() {
     Widget current = child;
 
     if (child == null && width == null && height == null)
-      current = new SizedBox(
-        width: double.INFINITY,
-        height: double.INFINITY
-      );
+      current = new ConstrainedBox(constraints: BoxConstraints.expand);
 
     if (padding != null)
       current = new Padding(padding: padding, child: current);
 
     if (decoration != null)
       current = new DecoratedBox(decoration: decoration, child: current);
 
     if (width != null || height != null)
       current = new SizedBox(
         width: width,
@@ skipping 185 matching lines @@
   }
 
   void remove() {
     RenderObjectWrapper ancestor = findAncestor(RenderObjectWrapper);
     assert(ancestor is RenderObjectWrapper);
     ancestor.detachChildRoot(this);
     super.remove();
   }
 
 }