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

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/overflow-scroll-body-appear-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [2008, 2096],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutView #document",
           "rect": [0, 0, 2008, 2096],
           "reason": "style change"
         },
         {
           "object": "LayoutView #document",
           "rect": [0, 585, 785, 15],
           "reason": "scroll"
         },
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [8, 16, 784, 2072],
           "reason": "style change"
         },
         {
-          "object": "LayoutBlockFlow P",
-          "rect": [8, 52, 784, 20],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutBlockFlow P",
-          "rect": [8, 16, 784, 20],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutText #text",
           "rect": [118, 52, 370, 19],
           "reason": "forced by layout"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [8, 16, 324, 19],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 52, 110, 19],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutView #document",
           "rect": [785, 0, 15, 585],
           "reason": "scroll"
         },
         {
           "object": "LayoutView #document",
           "rect": [785, 585, 15, 15],
           "reason": "scroll"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [488, 52, 4, 19],
-          "reason": "forced by layout"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutView #document",
       "reason": "scroll"
     },
     {
@@ skipping 52 matching lines @@
       "object": "LayoutText #text",
       "reason": "forced by layout"
     },
     {
       "object": "InlineTextBox '.'",
       "reason": "forced by layout"
     }
   ]
 }