Fix the bug that negative outline-offset is covered up by composited

third_party/WebKit/LayoutTests/paint/invalidation/repaint-composited-child-in-scrolled-container-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true
     },
     {
       "name": "LayoutBlockFlow (positioned) DIV id='outer'",
@@ skipping 35 matching lines @@
       "position": [285, 0],
       "bounds": [15, 285]
     },
     {
       "name": "Scroll Corner Layer",
       "position": [285, 285],
       "bounds": [15, 15],
       "drawsContent": true
     },
     {
+      "name": "Decoration Layer",
+      "bounds": [300, 300],
+      "drawsContent": true
+    },
+    {
       "name": "LayoutBlockFlow (positioned) DIV id='container'",
       "position": [-307, 8],
       "bounds": [600, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "backgroundColor": "#FF0000",
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV id='inner'",
           "rect": [0, 0, 600, 600],
           "reason": "style change"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow DIV id='inner'",
       "reason": "style change"
     }
   ]
 }