The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5bd15ff64323a54e5e0b33011209355eeec7fad4

commit 5bd15ff64323a54e5e0b33011209355eeec7fad4
Author: Iker Jamardo <ijamardo@chromium.org>
Date: Thu May 31 07:07:03 2018

WebXR: Add pause/resume for ARCoreDevice

Add pause/resume on focus changes in ARCoreDevice to correctly
pause/resume ARCore.

Bug:  838513 ,  837550 

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr
Change-Id: I40f11c48c6a9f15b3a558546e017545f0ab66a1d
Reviewed-on: https://chromium-review.googlesource.com/1046112
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Reviewed-by: Bill Orr <billorr@chromium.org>
Commit-Queue: Iker Jamardo <ijamardo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563168}
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore.h
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_device.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_device.h
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_gl.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_gl.h
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_impl.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/arcore_impl.h
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/fake_arcore.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/android/vr/arcore_device/fake_arcore.h
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/chrome/browser/vr/service/vr_display_host.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/device/vr/vr_device_base.cc
[modify] https://crrev.com/5bd15ff64323a54e5e0b33011209355eeec7fad4/device/vr/vr_device_base.h

This is fixed. Issue 845283 tracks a better solution for signaling when to pause/resume. We also want to ensure there is a good user experience (issue 850283).