Stacked does not repaint when its position changes

We were marking the parent *Widget's* render object as needing layout, but
we actually need to walk up the component tree until we find the parent
*RenderObjectWrapper* so we can mark actually mark the parent render object as
needing layout.

Fixes #408
1 file changed
tree: f10d43e4aa6bb3b3f86bdafa40a22da5daaedec2
  1. packages/