Paint backgrounds of a table section/row in one display item

third_party/WebKit/LayoutTests/platform/mac/paint/invalidation/table/composited-table-background-initial-empty-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutTableRow TR id='target'",
           "rect": [8, 94, 186, 64],
           "reason": "style change"
         }
       ]
     },
     {
       "name": "LayoutTableCell TD",
       "position": [72, 94],
       "bounds": [59, 64],
       "drawsContent": true
     }
   ],
   "objectPaintInvalidations": [
     {
-      "object": "LayoutTableCell TD",
-      "reason": "style change"
-    },
-    {
-      "object": "RowBackground",
-      "reason": "style change"
-    },
-    {
-      "object": "LayoutTableCell TD",
-      "reason": "style change"
-    },
-    {
       "object": "LayoutTableRow TR id='target'",
       "reason": "style change"
     }
   ]
 }