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

third_party/WebKit/LayoutTests/paint/invalidation/bugzilla-6278-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [10, 132, 292, 144],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [10, 281, 292, 50],
           "reason": "bounds change"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [10, 132, 276, 143],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutBlockFlow DIV",
           "rect": [10, 132, 242, 180],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [10, 317, 242, 50],
           "reason": "bounds change"
         },
         {
           "object": "LayoutTableCell TD id='col1'",
           "rect": [10, 331, 242, 36],
           "reason": "incremental"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [10, 132, 240, 179],
-          "reason": "forced by layout"
-        },
-        {
           "object": "LayoutTableCell TD id='target'",
           "rect": [254, 132, 52, 235],
           "reason": "bounds change"
         },
         {
           "object": "LayoutTableCell TD id='col1'",
           "rect": [252, 132, 50, 199],
           "reason": "incremental"
         }
       ]
@@ skipping 60 matching lines @@
       "object": "LayoutBlockFlow DIV",
       "reason": "bounds change"
     },
     {
       "object": "LayoutTableCell TD id='target'",
       "reason": "bounds change"
     }
   ]
 }