Not sure if this is useful/relevant, but this is mentioned in other bugs on similar topic,

https://cs.chromium.org/chromium/src/ui/chromeos/devicetype_utils.h

Yep, thanks, Nigel! That should be what we need here. It doesn't have "tablet" as a device type, but it's a big improvement nonetheless. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0bc0346d867e12764896dde5b54d388ba427ffdc

commit 0bc0346d867e12764896dde5b54d388ba427ffdc
Author: Regan Hsu <hsuregan@chromium.org>
Date: Tue Dec 04 18:54:47 2018

[CrOS MultiDevice] Fix notification strings to be form-factor specific

Notifications refer to the current device as a "Chromebook" even when it
might be a Chromebox or Tablet. We should ensure that these descriptions
are accurate based on form factor.

Bug:  900680 
Change-Id: I890db4eb0aff71ad0a67dac90dc50d2ed0bc1a3a
Reviewed-on: https://chromium-review.googlesource.com/c/1359458
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613618}
[modify] https://crrev.com/0bc0346d867e12764896dde5b54d388ba427ffdc/ash/ash_strings.grd
[modify] https://crrev.com/0bc0346d867e12764896dde5b54d388ba427ffdc/ash/multi_device_setup/multi_device_notification_presenter.cc
[modify] https://crrev.com/0bc0346d867e12764896dde5b54d388ba427ffdc/ash/multi_device_setup/multi_device_notification_presenter_unittest.cc

Some stakeholders have requested that we merge this to 72. It's a pretty trivial change. David is an M72 merge in the cards here still?

This bug requires manual review: There is .grd file changes and we are only 19 days from stable.
Please contact the milestone owner if you have questions.
Owners: govind@(Android), kariahda@(iOS), djmm@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

We can no longer accept any additional string changes.

OK, we'll just wait until M73.