Refactor fn2.dart, since it breached our 1000-line threshold.

sky/sdk/lib/framework/components2/floating_action_button.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 '../fn2.dart';
-import '../rendering/box.dart';
-import '../painting/shadows.dart';
-import '../theme2/colors.dart';
-import 'dart:sky' as sky;
-import 'ink_well.dart';
-import 'material.dart';
-
-// TODO(eseidel): This needs to change based on device size?
-// http://www.google.com/design/spec/layout/metrics-keylines.html#metrics-keylines-keylines-spacing
-const double _kSize = 56.0;
-
-class FloatingActionButton extends Component {
-
-  FloatingActionButton({ Object key, this.content, this.level: 0 })
-      : super(key: key);
-
-  final UINode content;
-  final int level;
-
-  UINode build() {
-    List<UINode> children = [];
-
-    if (content != null)
-      children.add(content);
-
-    return new Material(
-      content: new CustomPaint(
-        callback: (sky.Canvas canvas, Size size) {
-          const double radius = _kSize / 2.0;
-          sky.Paint paint = new sky.Paint()..color = Red[500];
-          var builder = new ShadowDrawLooperBuilder()
-            ..addShadow(const sky.Size(0.0, 5.0),
-                        const sky.Color(0x77000000),
-                        5.0);
-          paint.setDrawLooper(builder.build());
-          canvas.drawCircle(radius, radius, radius, paint);
-        },
-        child: new ClipOval(
-          child: new Container(
-            width: _kSize,
-            height: _kSize,
-            child: new InkWell(children: children)
-          )
-        )
-      ),
-      level: level);
-  }
-
-}