Fix padding on Sky home screen scrollable list

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 '../animation/scroll_behavior.dart';
 import 'basic.dart';
 import 'scrollable.dart';
 
 abstract class FixedHeightScrollable extends Scrollable {
 
-  FixedHeightScrollable({ String key, this.itemHeight, Color backgroundColor })
+  final EdgeDims padding;
+
+  FixedHeightScrollable({ String key, this.itemHeight, Color backgroundColor, this.padding })
       : super(key: key, backgroundColor: backgroundColor) {
     assert(itemHeight != null);
   }
 
   double itemHeight;
 
   void syncFields(FixedHeightScrollable source) {
     itemHeight = source.itemHeight;
     super.syncFields(source);
   }
 
   ScrollBehavior createScrollBehavior() => new OverscrollBehavior();
   OverscrollBehavior get scrollBehavior => super.scrollBehavior;
 
   int _itemCount = 0;
   int get itemCount => _itemCount;
   void set itemCount (int value) {
     if (_itemCount != value) {
       _itemCount = value;
-      scrollBehavior.contentsHeight = itemHeight * _itemCount;
+      double contentsHeight = itemHeight * _itemCount;
+      if (padding != null)
+         contentsHeight += padding.top + padding.bottom;
+      scrollBehavior.contentsHeight = contentsHeight;
     }
   }
 
   double _height;
   void _handleSizeChanged(Size newSize) {
     setState(() {
       _height = newSize.height;
       scrollBehavior.containerHeight = _height;
     });
   }
@@ skipping 23 matching lines @@
     }
 
     List<Widget> items = buildItems(itemShowIndex, itemShowCount);
     assert(items.every((item) => item.key != null));
 
     return new SizeObserver(
       callback: _handleSizeChanged,
       child: new ClipRect(
         child: new Transform(
           transform: transform,
-          child: new Block(items)
+          child: new Container(
+            padding: padding,
+            child: new Block(items)
+          )
         )
       )
     );
   }
 
   List<Widget> buildItems(int start, int count);
 
 }