Update reason after full paint invalidation

third_party/WebKit/LayoutTests/platform/win/paint/invalidation/forms/submit-focus-by-mouse-then-keydown-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutButton INPUT",
           "rect": [7, 7, 59, 24],
           "reason": "subtree"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [16, 11, 41, 16],
-          "reason": "subtree"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutButton INPUT",
       "reason": "subtree"
     },
     {
       "object": "LayoutBlockFlow (anonymous)",
       "reason": "subtree"
     },
     {
       "object": "RootInlineBox",
       "reason": "subtree"
     },
     {
       "object": "LayoutText #text",
       "reason": "subtree"
     },
     {
       "object": "InlineTextBox 'Submit'",
       "reason": "subtree"
     }
   ]
 }