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

sky/examples/widgets/spinning_mixed.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:sky' as sky;
-
-import 'package:sky/base/scheduler.dart';
-import 'package:sky/rendering/box.dart';
-import 'package:sky/rendering/flex.dart';
-import 'package:sky/rendering/sky_binding.dart';
-import 'package:sky/widgets/basic.dart';
-import 'package:sky/widgets/raised_button.dart';
-import 'package:sky/widgets/widget.dart';
-import 'package:vector_math/vector_math.dart';
-
-import '../lib/solid_color_box.dart';
-import '../../tests/resources/display_list.dart';
-
-// Solid colour, RenderObject version
-void addFlexChildSolidColor(RenderFlex parent, sky.Color backgroundColor, { int flex: 0 }) {
-  RenderSolidColorBox child = new RenderSolidColorBox(backgroundColor);
-  parent.add(child);
-  child.parentData.flex = flex;
-}
-
-// Solid colour, Widget version
-class Rectangle extends Component {
-  Rectangle(this.color, { String key }) : super(key: key);
-  final Color color;
-  Widget build() {
-    return new Flexible(
-      child: new Container(
-        decoration: new BoxDecoration(backgroundColor: color)
-      )
-    );
-  }
-}
-
-Widget builder() {
-  return new Flex([
-      new Rectangle(const Color(0xFF00FFFF)),
-      new Container(
-        padding: new EdgeDims.all(10.0),
-        margin: new EdgeDims.all(10.0),
-        decoration: new BoxDecoration(backgroundColor: const Color(0xFFCCCCCC)),
-        child: new RaisedButton(
-          child: new Flex([
-            new Image(src: "https://www.dartlang.org/logos/dart-logo.png"),
-            new Text('PRESS ME'),
-          ]),
-          onPressed: () => print("Hello World")
-        )
-      ),
-      new Rectangle(const Color(0xFFFFFF00)),
-    ],
-    direction: FlexDirection.vertical,
-    justifyContent: FlexJustifyContent.spaceBetween
-  );
-}
-
-double timeBase;
-RenderTransform transformBox;
-
-final TestRenderView tester = new TestRenderView();
-
-void rotate(double timeStamp) {
-  if (timeBase == null)
-    timeBase = timeStamp;
-  double delta = (timeStamp - timeBase) / 1000; // radians
-
-  transformBox.setIdentity();
-  transformBox.translate(transformBox.size.width / 2.0, transformBox.size.height / 2.0);
-  transformBox.rotateZ(delta);
-  transformBox.translate(-transformBox.size.width / 2.0, -transformBox.size.height / 2.0);
-}
-
-void main() {
-  // Because we're going to use Widgets, we want to initialise its
-  // SkyBinding, not use the default one. We don't really need to do
-  // this, because RenderBoxToWidgetAdapter does it for us, but
-  // it's good practice in case we happen to not have a
-  // RenderBoxToWidgetAdapter in our tree at startup, or in case we
-  // want a renderViewOverride.
-  WidgetSkyBinding.initWidgetSkyBinding();
-
-  RenderFlex flexRoot = new RenderFlex(direction: FlexDirection.vertical);
-
-  RenderProxyBox proxy = new RenderProxyBox();
-  new RenderBoxToWidgetAdapter(proxy, builder); // adds itself to proxy
-
-  addFlexChildSolidColor(flexRoot, const sky.Color(0xFFFF00FF), flex: 1);
-  flexRoot.add(proxy);
-  addFlexChildSolidColor(flexRoot, const sky.Color(0xFF0000FF), flex: 1);
-
-  transformBox = new RenderTransform(child: flexRoot, transform: new Matrix4.identity());
-  RenderPadding root = new RenderPadding(padding: new EdgeDims.all(20.0), child: transformBox);
-
-  SkyBinding.instance.root = root;
-  addPersistentFrameCallback(rotate);
-}