Reland "VR: Ensure we remove black overlay if VR is exited while entering."

This reverts commit 0062abf0e2d46669d756ad16493f684ecc38a832.

Reason for revert: Fixing...

Original change's description:
> Revert "VR: Ensure we remove black overlay if VR is exited while entering."
>
> This reverts commit 9f8158c12189567f8b9f4bcb44dd3cfc68ecd470.
>
> Reason for revert: Culprit of failed VR tests https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Nougat%20Phone%20Tester/6884
>
> Original change's description:
> > VR: Ensure we remove black overlay if VR is exited while entering.
> >
> > This fixes a failure mode where we shutdownVR after handling the VR NFC
> > broadcast, and fail to properly cancel VR entry.
> >
> > Also does some other random cleanup of comments/visibility.
> >
> > Bug: 862829
> > Change-Id: Ic382692d7255aa5893391a602a6c949b4b4d498b
> > Reviewed-on: https://chromium-review.googlesource.com/1138726
> > Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> > Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#575388}
>
> TBR=mthiesse@chromium.org,tiborg@chromium.org
>
> Change-Id: Ibe67ee8c09dc44ac34d40c3eaf890884b400fc24
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 862829
> Reviewed-on: https://chromium-review.googlesource.com/1140813
> Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
> Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#575725}

Change-Id: I71738aafff0b703083f465085fb71f54d047729b
Bug: 862829
Reviewed-on: https://chromium-review.googlesource.com/1142167
Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576173}
6 files changed