Optimize outline paint invalidation

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/outline-repaint-glitch-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [15, 391, 208, 68],
-          "reason": "outline"
+          "reason": "border box change"
         },
         {
           "object": "LayoutBlockFlow DIV",
           "rect": [15, 229, 208, 68],
-          "reason": "outline"
+          "reason": "border box change"
         },
         {
           "object": "LayoutBlockFlow DIV id='b'",
           "rect": [29, 435, 180, 20],
           "reason": "incremental"
         },
         {
           "object": "LayoutBlockFlow DIV id='a'",
           "rect": [29, 273, 180, 20],
           "reason": "incremental"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV",
-      "reason": "outline"
+      "reason": "border box change"
     },
     {
       "object": "LayoutBlockFlow DIV id='a'",
       "reason": "incremental"
     },
     {
       "object": "LayoutBlockFlow DIV",
-      "reason": "outline"
+      "reason": "border box change"
     },
     {
       "object": "LayoutBlockFlow DIV id='b'",
       "reason": "incremental"
     }
   ]
 }