Rename UINode to Widget.

sky/examples/stocks2/lib/stock_arrow.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/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
 import 'package:sky/theme2/colors.dart' as colors;
@@ skipping 10 matching lines @@
     double normalizedPercentChange = math.min(percentChange.abs(), maxPercent) / maxPercent;
     return 100 + (normalizedPercentChange * 8.0).floor() * 100;
   }
 
   Color _colorForPercentChange(double percentChange) {
     if (percentChange > 0)
       return colors.Green[_colorIndexForPercentChange(percentChange)];
     return colors.Red[_colorIndexForPercentChange(percentChange)];
   }
 
-  UINode build() {
+  Widget build() {
     // TODO(jackson): This should change colors with the theme
     Color color = _colorForPercentChange(percentChange);
     const double kSize = 40.0;
     var arrow = new CustomPaint(callback: (sky.Canvas canvas, Size size) {
       Paint paint = new Paint()..color = color;
       paint.strokeWidth = 1.0;
       var padding = paint.strokeWidth * 3.0;
       var r = kSize / 2.0 - padding;
       canvas.save();
       canvas.translate(padding, padding);
@@ skipping 24 matching lines @@
     });
 
     return new Container(
         child: arrow,
         width: kSize,
         height: kSize,
         margin: const EdgeDims.symmetric(horizontal: 5.0));
   }
 
 }