Don't invalidate rect if it's covered by fully invalidated parent's visual rect

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/selection-clear-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV id='firstLine'",
@@ skipping 12 matching lines @@
         },
         {
           "object": "LayoutBlockFlow (anonymous)",
           "rect": [8, 108, 100, 100],
           "reason": "bounds change"
         },
         {
           "object": "LayoutText #text",
           "rect": [8, 48, 92, 119],
           "reason": "layoutObject removal"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 48, 8, 19],
-          "reason": "layoutObject insertion"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutText #text",
       "reason": "layoutObject removal"
     },
     {
@@ skipping 48 matching lines @@
       "object": "LayoutBR BR",
       "reason": "location change"
     },
     {
       "object": "InlineTextBox '\n'",
       "reason": "location change"
     }
   ]
 }