Move example fn widgets into sky/framework/components

sky/examples/fn/widgets/buttonbase.dart

Index: sky/examples/fn/widgets/buttonbase.dart
diff --git a/sky/examples/fn/widgets/buttonbase.dart b/sky/examples/fn/widgets/buttonbase.dart
deleted file mode 100644
index a69202280188acaf268d3e7b3b446d76bc401dbd..0000000000000000000000000000000000000000
--- a/sky/examples/fn/widgets/buttonbase.dart
+++ /dev/null
@@ -1,28 +0,0 @@
-part of widgets;
-
-abstract class ButtonBase extends MaterialComponent {
-
-  bool _highlight = false;
-
-  ButtonBase({ Object key }) : super(key: key) {
-    events.listen('pointerdown', _handlePointerDown);
-    events.listen('pointerup', _handlePointerUp);
-    events.listen('pointercancel', _handlePointerCancel);
-  }
-
-  void _handlePointerDown(_) {
-    setState(() {
-      _highlight = true;
-    });
-  }
-  void _handlePointerUp(_) {
-    setState(() {
-      _highlight = false;
-    });
-  }
-  void _handlePointerCancel(_) {
-    setState(() {
-      _highlight = false;
-    });
-  }
-}