Chrome Version: 72.0.3602.2 (Official Build) dev (64-bit)
OS: Linux

What steps will reproduce the problem?
(1) Visit an IDN domain (I tested with https://xn--e1afmkfd.xn--80akhbyknj4f/).
(2) Trigger a notification. This can be done via the devtools console:
Notification.requestPermission().then(function (permission) {
  if (permission === "granted") {
    var notification = new Notification("Hi there!");
  }
}

What is the expected result?

The host should be displayed in unicode.

What happens instead?

The host displayed in the origin is in punycode.

I believe this is caused by the use of GURL::host() in platform_notification_service_impl.cc [1].

[1] https://cs.chromium.org/chromium/src/chrome/browser/notifications/platform_notification_service_impl.cc?l=349