Chrome Version: 67.0.3396.87
OS: Mac

What steps will reproduce the problem?
(1) Configure an administrator policy that sets DefaultSearchProviderEnabled = false (*)
(2) Restart Chrome
(3)

(*) See https://www.chromium.org/administrators/linux-quick-start for how to set policies. For example, in /etc/chromium/policies/managed/chrome_variations.json (applies to Chromium):
{
  "DefaultSearchProviderEnabled": false
}

Note that the NTP has a scrollbar, even though there's no content that requires it.