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

third_party/WebKit/LayoutTests/paint/invalidation/ruby-flipped-blocks-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [8, 8, 30, 40],
           "reason": "forced by layout"
         },
         {
-          "object": "LayoutRubyBase (anonymous)",
-          "rect": [8, 28, 20, 20],
-          "reason": "style change"
-        },
-        {
           "object": "LayoutRubyRun (anonymous)",
           "rect": [8, 28, 20, 20],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutText #text",
-          "rect": [8, 28, 20, 20],
-          "reason": "style change"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 8, 20, 20],
-          "reason": "forced by layout"
-        },
-        {
-          "object": "LayoutText #text",
           "rect": [28, 33, 10, 10],
           "reason": "style change"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV",
       "reason": "forced by layout"
@@ skipping 34 matching lines @@
       "object": "LayoutText #text",
       "reason": "style change"
     },
     {
       "object": "InlineTextBox 'b'",
       "reason": "style change"
     }
   ]
 }