Remove dead VR Pause code.

We have several concepts of focus/active/etc for VR headsets. One of
these represents menu mode, where the browser temporarily unfocuses a
VR experience.  This is not hooked up currently, so we have stale code.

This dead code would otherwise need to be converted when VRDevice is
mojoified, so removing for now.  If we want to add back a similar  way
to pause experiences, we can easily add it back.

BUG=795510

Change-Id: Ifba2d7d6f23ba668c5f259a9326acb4983f13836
Reviewed-on: https://chromium-review.googlesource.com/1068097
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Bill Orr <billorr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560697}
10 files changed