Move sky/examples to sky/sdk/lib/example, and code changes to support that change. Fixes T277.

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/theme/colors.dart' as colors;
-import 'package:sky/widgets/basic.dart';
-
-class StockArrow extends Component {
-
-  StockArrow({ String key, this.percentChange }) : super(key: key);
-
-  final double percentChange;
-
-  int _colorIndexForPercentChange(double percentChange) {
-    double maxPercent = 10.0;
-    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)];
-  }
-
-  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;
-      const double padding = 2.0;
-      assert(padding > paint.strokeWidth / 2.0); // make sure the circle remains inside the box
-      double r = (kSize - padding) / 2.0; // radius of the circle
-      double centerX = padding + r;
-      double centerY = padding + r;
-
-      // Draw the arrow.
-      double w = 8.0;
-      double h = 5.0;
-      double arrowY;
-      if (percentChange < 0.0) {
-        h = -h;
-        arrowY = centerX + 1.0;
-      } else {
-        arrowY = centerX - 1.0;
-      }
-      Path path = new Path();
-      path.moveTo(centerX, arrowY - h); // top of the arrow
-      path.lineTo(centerX + w, arrowY + h);
-      path.lineTo(centerX - w, arrowY + h);
-      path.close();
-      paint.setStyle(sky.PaintingStyle.fill);
-      canvas.drawPath(path, paint);
-
-      // Draw a circle that circumscribes the arrow.
-      paint.setStyle(sky.PaintingStyle.stroke);
-      canvas.drawCircle(centerX, centerY, r, paint);
-    });
-
-    return new Container(
-      child: arrow,
-      width: kSize,
-      height: kSize,
-      margin: const EdgeDims.symmetric(horizontal: 5.0)
-    );
-  }
-
-}