The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7b5868ec669060c022c42a8f02d5ab1b775aafd4

commit 7b5868ec669060c022c42a8f02d5ab1b775aafd4
Author: Anna Offenwanger <offenwanger@chromium.org>
Date: Tue Feb 27 20:15:05 2018

Add Duration UKM for Presentation sessions

Added a Duration metric for when a vr presentation is happening. Renamed
TimeOnPage to Duration under PageSession.

Bug:  808586 
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_vr;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I5ab5810278399cc69c495fb44e89bc350d260c3f
Reviewed-on: https://chromium-review.googlesource.com/923024
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Bill Orr <billorr@chromium.org>
Commit-Queue: Anna Offenwanger <offenwanger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539534}
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/android/vr/vr_shell.cc
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/android/vr/vr_usage_monitor.cc
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/android/vr/vr_usage_monitor.h
[add] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/android/vr/vr_usage_monitor_unittest.cc
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/vr/metrics_helper.cc
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/browser/vr/mode.h
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/chrome/test/BUILD.gn
[modify] https://crrev.com/7b5868ec669060c022c42a8f02d5ab1b775aafd4/tools/metrics/ukm/ukm.xml

Your change meets the bar and is auto-approved for M66. Please go ahead and merge the CL to branch 3359 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), josafat@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

moving to M67 then. If you still intend to try merge back to 66, please feel free to move back to 66.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/42a1454b18c8a5762ad423d2721ba3233f60bc39

commit 42a1454b18c8a5762ad423d2721ba3233f60bc39
Author: Anna Offenwanger <offenwanger@chromium.org>
Date: Thu Apr 05 16:38:21 2018

Add XR.WebXR.PresentationSession.StartAction metric

Add a metric to track how presentation was started.

Bug:  808586 
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;master.tryserver.chromium.linux:linux_vr;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I2abda74f64ddc5fed58c6b71fbebcdddd2f8bab8
Reviewed-on: https://chromium-review.googlesource.com/986976
Commit-Queue: Anna Offenwanger <offenwanger@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548451}
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/android/vr/vr_shell.cc
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/android/vr/vr_shell.h
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/android/vr/vr_shell_delegate.cc
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/android/vr/vr_shell_delegate.h
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/vr/metrics/session_metrics_helper.cc
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/chrome/browser/vr/metrics/session_metrics_helper.h
[modify] https://crrev.com/42a1454b18c8a5762ad423d2721ba3233f60bc39/tools/metrics/ukm/ukm.xml