Move example fn widgets into sky/framework/components

sky/framework/components/button.dart

Index: sky/framework/components/button.dart
diff --git a/sky/examples/fn/widgets/button.dart b/sky/framework/components/button.dart
similarity index 65%
rename from sky/examples/fn/widgets/button.dart
rename to sky/framework/components/button.dart
index 17ffa2524bc9f001fe348865d232ee76a69e81f2..159da90c71733248b514d9cc5264c87a02a29149 100644
--- a/sky/examples/fn/widgets/button.dart
+++ b/sky/framework/components/button.dart
@@ -1,8 +1,12 @@
-part of widgets;
+// 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.
 
-class Button extends ButtonBase {
+import '../fn.dart';
+import 'button_base.dart';
 
-  static Style _style = new Style('''
+class Button extends ButtonBase {
+  static final Style _style = new Style('''
     transform: translateX(0);
     display: inline-flex;
     border-radius: 4px;
@@ -13,7 +17,7 @@ class Button extends ButtonBase {
     margin: 5px;'''
   );
 
-  static Style _highlightStyle = new Style('''
+  static final Style _highlightStyle = new Style('''
     transform: translateX(0);
     display: inline-flex;
     border-radius: 4px;
@@ -31,8 +35,7 @@ class Button extends ButtonBase {
 
   Node build() {
     return new Container(
-      key: 'Button',
-      style: _highlight ? _highlightStyle : _style,
+      style: highlight ? _highlightStyle : _style,
       children: [super.build(), content]
     );
   }