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

sky/sdk/lib/widgets/scaffold.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 '../rendering/box.dart';
 import '../rendering/object.dart';
 import '../theme/view_configuration.dart';
 import 'widget.dart';
 
 enum ScaffoldSlots {
@@ skipping 57 matching lines @@
         this[slot] = null;
         return slot;
       }
     }
     return null;
   }
 
   bool get sizedByParent => true;
   void performResize() {
     size = constraints.constrain(Size.infinite);
-    assert(size.width < double.INFINITY);
-    assert(size.height < double.INFINITY);
+    assert(!size.isInfinite);
   }
 
   // TODO(eseidel): These change based on device size!
   // http://www.google.com/design/spec/layout/metrics-keylines.html#metrics-keylines-keylines-spacing
   static const kButtonX = 16.0; // left from right edge of body
   static const kButtonY = 16.0; // up from bottom edge of body
 
   void performLayout() {
     double bodyHeight = size.height;
     double bodyPosition = 0.0;
@@ skipping 124 matching lines @@
   void syncRenderObject(Widget old) {
     super.syncRenderObject(old);
     _toolbar = syncChild(_toolbar, old is Scaffold ? old._toolbar : null, ScaffoldSlots.toolbar);
     _body = syncChild(_body, old is Scaffold ? old._body : null, ScaffoldSlots.body);
     _statusBar = syncChild(_statusBar, old is Scaffold ? old._statusBar : null, ScaffoldSlots.statusBar);
     _drawer = syncChild(_drawer, old is Scaffold ? old._drawer : null, ScaffoldSlots.drawer);
     _floatingActionButton = syncChild(_floatingActionButton, old is Scaffold ? old._floatingActionButton : null, ScaffoldSlots.floatingActionButton);
   }
 
 }