Oobe: add debug overlay for parental-handoff screen

Bug: 1134567
Change-Id: I8b278acaa2fab943ce136d7d7de578da7a63e992
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2520778Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Yunke Zhou <yunkez@google.com>
Cr-Commit-Position: refs/heads/master@{#824800}

chrome/browser/resources/chromeos/login/debug/debug.js

@@ -902,6 +902,19 @@ cr.define('cr.ui.login.debug', function() {
       id: 'assistant-optin-flow',
       kind: ScreenKind.NORMAL,
     },
+    {
+      id: 'parental-handoff',
+      kind: ScreenKind.NORMAL,
+      states: [{
+        id: 'parental-handoff',
+        data: {
+          title: 'Now it\'s Child 1\'s turn',
+          subtitle:
+              'You can hand this Chromebook to Child 1. Setup is almost done,' +
+              ' then it\'s time to explore.'
+        },
+      }],
+    },
     {
       id: 'multidevice-setup',
       kind: ScreenKind.NORMAL,