Don't let PaintInvalidationLocationChange shadow other reasons

third_party/WebKit/LayoutTests/platform/linux/fast/repaint/subtree-root-skipped-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV id='inner-editor'",
           "rect": [10, 11, 150, 16],
           "reason": "invalidate paint rectangle"
         },
         {
           "object": "LayoutText #text",
           "rect": [10, 11, 35, 16],
           "reason": "full"
         },
         {
           "object": "LayoutBlockFlow (positioned) DIV id='div'",
           "rect": [8, 288, 10, 20],
-          "reason": "location change"
+          "reason": "bounds change"
         },
         {
           "object": "InlineTextBox ''",
           "reason": "full"
         },
         {
           "object": "InlineTextBox 'PASS'",
           "reason": "full"
         },
         {
           "object": "RootInlineBox",
           "reason": "full"
         }
       ]
     }
   ]
 }