The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/05621d9dfebb20f63cceeccaedb8eb0fe39fdc21

commit 05621d9dfebb20f63cceeccaedb8eb0fe39fdc21
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Thu Nov 23 19:41:44 2017

VR: Handle density changing after Chrome is backgrounded in VR on S8(+)

If the user goes to DD home, then changes their device resolution before
returning to Chrome, we can't ignore the density change like we normally
would. This CL detects when the density is not what we expected it to
be when resuming Chrome after using VR on the S8(+), and recreates the
activity.

Bug:  787915 
Change-Id: I657dad28aa385e43344c69d8ac175766be3ba333
Reviewed-on: https://chromium-review.googlesource.com/788270
Reviewed-by: Yash Malik <ymalik@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519006}
[modify] https://crrev.com/05621d9dfebb20f63cceeccaedb8eb0fe39fdc21/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java

mthiesse@, do you think we should add a specific manual test case for this to be run on a weekly basis? If not, I'll drop it from my radar. Thanks.

While this would be easy to manually test, I'm not sure if it's worth your time :P

The user would basically have to intentionally go out of their way in order to hit this issue if it regresses in the future.

Do you have anything like a set of even less frequently run manual tests, like once per release or something like that?

We do have a category of manual tests that are documented but not a part of the regular test pass. They aren't run every release though. They are low pri. and have typically been run once only. 

It would be worth our manual test team to look into having a set of test cases that are run per release. I'll bring that up for discussion along with this particular case, thanks!