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

third_party/WebKit/LayoutTests/platform/mac/paint/invalidation/caret-contenteditable-content-after-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV id='editor'",
           "rect": [3, 39, 794, 28],
           "reason": "style change"
         },
         {
           "object": "LayoutBlockFlow DIV id='editor'",
           "rect": [3, 39, 794, 28],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow DIV id='editor'",
           "rect": [3, 39, 794, 28],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow DIV id='editor'",
           "rect": [3, 39, 794, 28],
           "reason": "forced by layout"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [8, 44, 23, 18],
-          "reason": "full"
-        },
-        {
-          "object": "LayoutText #text",
-          "rect": [8, 44, 16, 18],
-          "reason": "full"
-        },
-        {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [30, 44, 9, 18],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [23, 44, 9, 18],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [23, 44, 9, 18],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [15, 44, 9, 18],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [15, 44, 9, 18],
           "reason": "forced by layout"
         },
         {
-          "object": "LayoutText #text",
-          "rect": [8, 44, 8, 18],
-          "reason": "layoutObject insertion"
-        },
-        {
           "object": "LayoutTextFragment (anonymous)",
           "rect": [8, 44, 8, 18],
           "reason": "forced by layout"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV id='editor'",
@@ skipping 87 matching lines @@
       "object": "LayoutTextFragment (anonymous)",
       "reason": "forced by layout"
     },
     {
       "object": "InlineTextBox 'x'",
       "reason": "forced by layout"
     }
   ]
 }