Simplify incremental paint invalidation

third_party/WebKit/LayoutTests/paint/invalidation/compositing/resize-repaint-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true
     },
     {
       "name": "LayoutBlockFlow DIV id='resizing'",
       "position": [8, 8],
       "bounds": [402, 207],
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV id='resizing'",
           "rect": [0, 104, 402, 103],
           "reason": "incremental"
         },
         {
-          "object": "LayoutBlockFlow DIV id='resizing'",
-          "rect": [0, 105, 402, 102],
-          "reason": "incremental"
-        },
-        {
           "object": "LayoutBlockFlow DIV",
           "rect": [2, 155, 398, 50],
           "reason": "layoutObject insertion"
         },
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [2, 104, 398, 50],
           "reason": "layoutObject insertion"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV id='resizing'",
       "reason": "incremental"
     },
     {
       "object": "LayoutBlockFlow DIV",
       "reason": "layoutObject insertion"
     },
     {
       "object": "LayoutBlockFlow DIV",
       "reason": "layoutObject insertion"
     }
   ]
 }