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

third_party/WebKit/LayoutTests/paint/invalidation/fixed-to-relative-position-with-absolute-child-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 2016],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [8, 8, 784, 2000],
           "reason": "style change"
         },
         {
           "object": "LayoutBlockFlow (positioned) DIV class='absolute green'",
           "rect": [108, 308, 100, 100],
           "reason": "subtree"
         },
         {
           "object": "LayoutBlockFlow (positioned) DIV class='absolute green'",
           "rect": [108, 300, 100, 100],
           "reason": "subtree"
         },
         {
-          "object": "LayoutBlockFlow (relative positioned) DIV id='container' class='fixed blue'",
-          "rect": [8, 208, 100, 100],
-          "reason": "subtree"
-        },
-        {
           "object": "LayoutBlockFlow (positioned) DIV id='container' class='fixed blue'",
           "rect": [8, 200, 100, 100],
           "reason": "subtree"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow (positioned) DIV id='container' class='fixed blue'",
@@ skipping 19 matching lines @@
       "object": "LayoutBlockFlow (relative positioned) DIV id='container' class='fixed blue'",
       "reason": "subtree"
     },
     {
       "object": "LayoutBlockFlow (positioned) DIV class='absolute green'",
       "reason": "subtree"
     }
   ]
 }