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

third_party/WebKit/LayoutTests/paint/invalidation/table-col-background-offset-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutTableCol COL id='col'",
           "rect": [8, 108, 210, 104],
           "reason": "style change"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
-      "object": "LayoutTableCell TD",
+      "object": "LayoutTableSection TBODY",
       "reason": "style change"
     },
     {
       "object": "LayoutTableCol COL id='col'",
       "reason": "style change"
     }
   ]
 }