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

third_party/WebKit/LayoutTests/paint/invalidation/scroll-in-fixed-layer-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 2016],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
-          "object": "LayoutBlockFlow (positioned) DIV class='absolute green'",
-          "rect": [100, 1150, 100, 100],
-          "reason": "subtree"
-        },
-        {
-          "object": "LayoutBlockFlow (positioned) DIV class='absolute red'",
-          "rect": [100, 1150, 100, 100],
-          "reason": "subtree"
-        },
-        {
           "object": "LayoutBlockFlow (positioned) DIV id='moveMe' class='fixed clipped'",
           "rect": [100, 1150, 100, 100],
           "reason": "subtree"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow (positioned) DIV id='moveMe' class='fixed clipped'",
       "reason": "subtree"
     },
     {
       "object": "LayoutBlockFlow (positioned) DIV class='absolute green'",
       "reason": "subtree"
     },
     {
       "object": "LayoutBlockFlow (positioned) DIV class='absolute red'",
       "reason": "subtree"
     }
   ]
 }