Calculate paint invalidation rect for scrollbars

third_party/WebKit/LayoutTests/platform/linux/fast/repaint/line-flow-with-floats-2-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [485, 0, 15, 600],
         [372, 384, 48, 81],
@@ skipping 23 matching lines @@
         [0, 0, 485, 600]
       ],
       "paintInvalidationClients": [
         "InlineTextBox 'straightened\n'",
         "InlineTextBox 'out, and was going to give the hedgehog a'",
         "RootInlineBox",
         "InlineTextBox 'blow with its head, it\n'",
         "InlineTextBox ''",
         "InlineTextBox ' twist itself round and look up in her'",
         "RootInlineBox",
-        "VerticalScrollbar",
-        "LayoutIFrame IFRAME id='iframe'",
         "LayoutBlockFlow HTML",
         "LayoutBlockFlow P",
         "LayoutBlockFlow P",
         "LayoutText #text",
         "InlineTextBox 'The chief difficulty Alice found at first was in managing her'",
         "InlineTextBox 'flamingo: she succeeded in getting its body tucked away,'",
         "InlineTextBox 'comfortably enough, under her arm, with its legs hanging'",
         "InlineTextBox 'down,\n'",
         "InlineTextBox 'but generally, just as she had got its neck nicely'",
         "InlineTextBox 'straightened\n'",
@@ skipping 43 matching lines @@
         "InlineTextBox 'her head!\u2019 about'",
         "InlineTextBox 'once in a minute.\n'",
         "LayoutText #text",
         "InlineTextBox 'Alice began to feel very uneasy: to be sure, she had not as\n'",
         "InlineTextBox 'yet had'",
         "InlineTextBox 'any dispute with the Queen, but she knew that it might\n'",
         "InlineTextBox 'happen any'",
         "InlineTextBox 'minute, \u2018and then,\u2019 thought she, \u2018what would become of\n'",
         "InlineTextBox 'me?'",
         "InlineTextBox 'They\u2019re dreadfully fond of beheading people here; the great'",
-        "InlineTextBox 'wonder is, that there\u2018s any one left alive!\u2019'"
+        "InlineTextBox 'wonder is, that there\u2018s any one left alive!\u2019'",
+        "VerticalScrollbar"
       ]
     }
   ]
 }