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

sky/examples/rendering/touch_demo.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';
-import 'dart:sky';
-
-import 'package:sky/rendering/box.dart';
-import 'package:sky/rendering/object.dart';
-import 'package:sky/rendering/paragraph.dart';
-import 'package:sky/rendering/sky_binding.dart';
-import 'package:sky/rendering/stack.dart';
-import 'package:sky/theme/colors.dart';
-
-// Material design colors. :p
-List<Color> colors = [
-  Teal[500],
-  Amber[500],
-  Purple[500],
-  LightBlue[500],
-  DeepPurple[500],
-  Lime[500],
-];
-
-class Dot {
-  final Paint _paint;
-  double x = 0.0;
-  double y = 0.0;
-  double radius = 0.0;
-
-  Dot({ Color color }) : _paint = new Paint()..color = color;
-
-  void update(PointerEvent event) {
-    x = event.x;
-    y = event.y;
-    radius = 5 + (95 * event.pressure);
-  }
-
-  void paint(RenderCanvas canvas) {
-    canvas.drawCircle(x, y, radius, _paint);
-  }
-}
-
-class RenderTouchDemo extends RenderBox {
-  Map<int, Dot> dots = new Map();
-
-  RenderTouchDemo();
-
-  void handleEvent(Event event, BoxHitTestEntry entry) {
-    switch (event.type) {
-      case 'pointerdown':
-        Color color = colors[event.pointer.remainder(colors.length)];
-        dots[event.pointer] = new Dot(color: color)..update(event);
-        break;
-      case 'pointerup':
-        dots.remove(event.pointer);
-        break;
-      case 'pointercancel':
-        dots = new Map();
-        break;
-      case 'pointermove':
-        dots[event.pointer].update(event);
-        break;
-    }
-    markNeedsPaint();
-  }
-
-  void performLayout() {
-    size = constraints.constrain(Size.infinite);
-  }
-
-  void paint(RenderCanvas canvas) {
-    Paint white = new Paint()..color = const Color(0xFFFFFFFF);
-    canvas.drawRect(new Rect.fromSize(size), white);
-    for (Dot dot in dots.values)
-      dot.paint(canvas);
-  }
-}
-
-void main() {
-  var paragraph = new RenderParagraph(new InlineText("Touch me!"));
-  var stack = new RenderStack(children: [
-    new RenderTouchDemo(),
-    paragraph,
-  ]);
-  // Prevent the RenderParagraph from filling the whole screen so
-  // that it doesn't eat events.
-  paragraph.parentData..top = 40.0
-                      ..left = 20.0;
-  new SkyBinding(root: stack);
-}