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

sky/sdk/lib/framework/widgets/scrollable.dart

Index: sky/sdk/lib/framework/widgets/scrollable.dart
diff --git a/sky/sdk/lib/framework/components2/scrollable.dart b/sky/sdk/lib/framework/widgets/scrollable.dart
similarity index 99%
rename from sky/sdk/lib/framework/components2/scrollable.dart
rename to sky/sdk/lib/framework/widgets/scrollable.dart
index dee2c137335f2e4647d5b4a3700459085341f169..16478f4652d6164ec227d41d3568a0b5bac6180a 100644
--- a/sky/sdk/lib/framework/components2/scrollable.dart
+++ b/sky/sdk/lib/framework/widgets/scrollable.dart
@@ -2,13 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:math' as math;
+import 'dart:sky' as sky;
+
 import '../animation/generators.dart';
 import '../animation/mechanics.dart';
 import '../animation/scroll_behavior.dart';
-import '../fn2.dart';
 import '../theme/view_configuration.dart' as config;
-import 'dart:math' as math;
-import 'dart:sky' as sky;
+import 'wrappers.dart';
 
 const double _kMillisecondsPerSecond = 1000.0;