Card "swipe-away" dismiss version 3: Uses BlockViewport

sky/sdk/lib/widgets/block_viewport.dart

Index: sky/sdk/lib/widgets/block_viewport.dart
diff --git a/sky/sdk/lib/widgets/block_viewport.dart b/sky/sdk/lib/widgets/block_viewport.dart
index e53240ae823b3fcd54ee5911301fff1814014299..8aa0f0c3756dd5379739ca19977e2cf0cc7417af 100644
--- a/sky/sdk/lib/widgets/block_viewport.dart
+++ b/sky/sdk/lib/widgets/block_viewport.dart
@@ -100,7 +100,7 @@ class BlockViewport extends RenderObjectWrapper {
     return right;
   }
 
-  bool _dirty = false;
+  bool _dirty = true;
 
   bool retainStatefulNodeIfPossible(BlockViewport newNode) {
     retainStatefulRenderObjectWrapper(newNode);
@@ -126,7 +126,7 @@ class BlockViewport extends RenderObjectWrapper {
         assert(_currentStartIndex >= 0);
         assert(builder != null);
         assert(root != null);
-        int lastIndex = _currentStartIndex + _currentChildCount;
+        int lastIndex = _currentStartIndex + _currentChildCount - 1;
         for (int index = _currentStartIndex; index <= lastIndex; index += 1) {
           Widget widget = builder(index);
           assert(widget != null);