Fork some more files from the old framework, so that the transition will be easier to perform.

sky/sdk/lib/widgets/fixed_height_scrollable.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 'package:vector_math/vector_math.dart';
 
-import '../framework/animation/scroll_behavior.dart';
+import '../animation/scroll_behavior.dart';
 import 'basic.dart';
 import 'scrollable.dart';
 
 abstract class FixedHeightScrollable extends Scrollable {
 
   FixedHeightScrollable({ String key, this.itemHeight, Color backgroundColor })
       : super(key: key, backgroundColor: backgroundColor) {
     assert(itemHeight != null);
   }
 
@@ skipping 58 matching lines @@
           transform: transform,
           child: new Block(items)
         )
       )
     );
   }
 
   List<Widget> buildItems(int start, int count);
 
 }