Update reason after full paint invalidation

third_party/WebKit/LayoutTests/paint/invalidation/content-into-overflow-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow (positioned) DIV",
           "rect": [8, 211, 106, 53],
           "reason": "incremental"
         },
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [8, 308, 100, 100],
           "reason": "became visible"
         },
         {
-          "object": "LayoutBlockFlow DIV id='target3'",
-          "rect": [8, 388, 100, 20],
-          "reason": "layoutObject insertion"
-        },
-        {
           "object": "LayoutBlockFlow (positioned) DIV",
           "rect": [61, 8, 53, 106],
           "reason": "incremental"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow (positioned) DIV",
       "reason": "incremental"
     },
     {
       "object": "LayoutBlockFlow (positioned) DIV",
       "reason": "incremental"
     },
     {
       "object": "LayoutBlockFlow DIV",
       "reason": "became visible"
     },
     {
       "object": "LayoutBlockFlow DIV id='target3'",
       "reason": "layoutObject insertion"
     }
   ]
 }