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

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/bugzilla-7235-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow (anonymous)",
           "rect": [8, 156, 784, 20],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow (positioned) DIV id='t'",
           "rect": [8, 176, 100, 100],
           "reason": "layoutObject insertion"
-        },
-        {
-          "object": "LayoutInline (relative positioned) SPAN id='p'",
-          "rect": [8, 156, 4, 19],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 156, 4, 19],
-          "reason": "forced by layout"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow (anonymous)",
       "reason": "forced by layout"
     },
     {
@@ skipping 16 matching lines @@
       "object": "InlineTextBox '\u00A0'",
       "reason": "forced by layout"
     },
     {
       "object": "LayoutBlockFlow (positioned) DIV id='t'",
       "reason": "layoutObject insertion"
     }
   ]
 }