Turns out S8 running O is the same - it no longer changes density entering VR.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b1e9929be181b111945d35cf636edc935ecb4793

commit b1e9929be181b111945d35cf636edc935ecb4793
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Thu Mar 22 18:57:27 2018

VR: Daydream Home launch Samsung device support

This CL adds support for the S8/S9 running O, which no longer change
resolution when entering VR.

However, the user can still change resolution manually and Chrome could
end up in the wrong resolution when launched from Daydream, so we handle
this case by just killing the process and returning to Daydream, so that
when Chrome is re-launched it's launched into the correct density. It
turned out to be way too difficult to properly support Activity
recreation while avoiding showing 2D UI to users.

Bug:  817987 ,  822292 
Change-Id: Ia8fa7bca41831810c2fa9f17088ba3049c6253f3
Reviewed-on: https://chromium-review.googlesource.com/971942
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Yash Malik <ymalik@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545178}
[modify] https://crrev.com/b1e9929be181b111945d35cf636edc935ecb4793/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
[modify] https://crrev.com/b1e9929be181b111945d35cf636edc935ecb4793/chrome/android/java/src/org/chromium/chrome/browser/vr/VrMainActivity.java
[modify] https://crrev.com/b1e9929be181b111945d35cf636edc935ecb4793/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java