Invalidate objects when containing block changed

third_party/WebKit/LayoutTests/fast/repaint/reflection-invalidation-after-display-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [300, 8, 450, 200],
-        [300, 8, 450, 200],
         [300, 8, 200, 200]
       ],
       "paintInvalidationClients": [
         "LayoutBlockFlow (positioned) DIV id='box' class='green box'",
         "LayoutBlockFlow (positioned) DIV id='box' class='green box'"
       ]
     }
   ]
 }