Introduce sky.Sky.zero

sky/examples/raw/sector_layout.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:math' as math;
 import 'dart:sky' as sky;
 import 'package:sky/framework/app.dart';
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/rendering/object.dart';
 
@@ skipping 383 matching lines @@
     markNeedsLayout();
   }
 
   void setParentData(RenderObject child) {
     if (child.parentData is! SectorParentData)
       child.parentData = new SectorParentData();
   }
 
   sky.Size getIntrinsicDimensions(BoxConstraints constraints) {
     if (child == null)
-      return constraints.constrain(new sky.Size(0.0, 0.0));
+      return constraints.constrain(sky.Size.zero);

[Hixie, 2015/06/08 17:01:53]

You should be able to remove the sky. part now.

     assert(child is RenderSector);
     assert(child.parentData is SectorParentData);
     assert(!constraints.isInfinite);
     double maxChildDeltaRadius = math.min(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
     SectorDimensions childDimensions = child.getIntrinsicDimensions(new SectorConstraints(maxDeltaRadius: maxChildDeltaRadius), innerRadius);
     double dimension = (innerRadius + childDimensions.deltaRadius) * 2.0;
     return constraints.constrain(new sky.Size(dimension, dimension));
   }
 
   void performLayout() {
     if (child == null) {
-      size = constraints.constrain(new sky.Size(0.0, 0.0));
+      size = constraints.constrain(sky.Size.zero);
     } else {
       assert(child is RenderSector);
       assert(!constraints.isInfinite);
       print("constraint maxes: ${constraints.maxWidth} and ${constraints.maxHeight}");
       double maxChildDeltaRadius = math.min(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
       print("maxChildDeltaRadius = $maxChildDeltaRadius");
       assert(child.parentData is SectorParentData);
       child.parentData.radius = innerRadius;
       child.parentData.theta = 0.0;
       child.layout(new SectorConstraints(maxDeltaRadius: maxChildDeltaRadius), parentUsesSize: true);
@@ skipping 72 matching lines @@
   rootCircle.add(new RenderSolidColor(const sky.Color(0xFF0000FF), desiredDeltaTheta: kTwoPi * 0.4));
   var stack = new RenderSectorSlice(padding: 2.0);
   stack.add(new RenderSolidColor(const sky.Color(0xFFFFFF00), desiredDeltaRadius: 20.0));
   stack.add(new RenderSolidColor(const sky.Color(0xFFFF9000), desiredDeltaRadius: 20.0));
   stack.add(new RenderSolidColor(const sky.Color(0xFF00FF00)));
   rootCircle.add(stack);
 
   var root = new RenderBoxToRenderSectorAdapter(innerRadius: 50.0, child: rootCircle);
   app = new AppView(root);
 }