Invalidate caret during paint invalidation

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/caret-outside-block-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
-          "object": "LayoutText #text",
+          "object": "LayoutBlockFlow DIV id='target'",
           "rect": [790, 7, 3, 21],
-          "reason": "invalidate paint rectangle"
+          "reason": "caret"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "Caret",
-      "reason": "invalidate paint rectangle"
+      "reason": "caret"
+    },
+    {
+      "object": "Caret",
+      "reason": "caret"
     }
   ]
 }