[css-grid] Only force full invalidation when grid item data change

third_party/WebKit/LayoutTests/fast/repaint/justify-self-overflow-change-expected.txt

 {
   "name": "Content Root Layer",
   "bounds": [800, 600],
   "children": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV class='item1'",
           "rect": [0, 52, 150, 300],
-          "reason": "style change"
+          "reason": "bounds change"
         },
         {
           "object": "LayoutBlockFlow DIV class='item1'",
           "rect": [-50, 52, 150, 300],
-          "reason": "style change"
-        },
-        {
-          "object": "LayoutBlockFlow DIV class='item2'",
-          "rect": [150, 52, 50, 300],
-          "reason": "style change"
+          "reason": "bounds change"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV class='item1'",
-      "reason": "style change"
+      "reason": "bounds change"
     },
     {
       "object": "LayoutBlockFlow DIV",
       "reason": "location change"
-    },
-    {
-      "object": "LayoutBlockFlow DIV class='item2'",
-      "reason": "style change"
     }
   ]
 }