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

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

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [2008, 2092],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutView #document",
           "rect": [0, 0, 2008, 2092],
           "reason": "style change"
         },
         {
           "object": "LayoutView #document",
           "rect": [0, 585, 785, 15],
           "reason": "scroll"
         },
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [8, 16, 784, 2068],
           "reason": "style change"
         },
         {
-          "object": "LayoutBlockFlow P",
-          "rect": [8, 50, 784, 18],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutBlockFlow P",
-          "rect": [8, 16, 784, 18],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutText #text",
           "rect": [127, 50, 390, 17],
           "reason": "forced by layout"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [8, 16, 348, 17],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 50, 120, 17],
-          "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": [516, 50, 5, 17],
-          "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"
     }
   ]
 }