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

sky/sdk/lib/framework/rendering/box.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:math' as math;
 import 'dart:sky' as sky;
-import 'dart:typed_data';
 import 'object.dart';
 import '../painting/box_painter.dart';
 import 'package:vector_math/vector_math.dart';
 import 'package:sky/framework/net/image_cache.dart' as image_cache;
 
 export '../painting/box_painter.dart';
 
 // GENERIC BOX RENDERING
 // Anything that has a concept of x, y, width, height is going to derive from this
 
@@ skipping 932 matching lines @@
 
   void defaultPaint(RenderObjectDisplayList canvas) {
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is ParentDataType);
       canvas.paintChild(child, child.parentData.position);
       child = child.parentData.nextSibling;
     }
   }
 }