As part of this, I'd also like us to log a UMA histogram that tells us how long it's been since the last policy fetch, per our email conversation. Bumping in priority to try to get in M60.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/659129b468b34cd565df37ae47dd0dbeb5970b2a

commit 659129b468b34cd565df37ae47dd0dbeb5970b2a
Author: antrim <antrim@chromium.org>
Date: Mon Aug 07 15:01:47 2017

UMA metrics for tracking the number of days
between policy fetches.

BUG= 704091 

Review-Url: https://codereview.chromium.org/2896863002
Cr-Commit-Position: refs/heads/master@{#492321}

[modify] https://crrev.com/659129b468b34cd565df37ae47dd0dbeb5970b2a/components/policy/core/common/cloud/cloud_policy_client.h
[modify] https://crrev.com/659129b468b34cd565df37ae47dd0dbeb5970b2a/components/policy/core/common/cloud/cloud_policy_service.cc
[modify] https://crrev.com/659129b468b34cd565df37ae47dd0dbeb5970b2a/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4b9250eebac7da0cf2138fceffb5af9855090940

commit 4b9250eebac7da0cf2138fceffb5af9855090940
Author: Denis Kuznetsov <antrim@google.com>
Date: Thu Feb 08 15:30:28 2018

Report Ephemeral status upon user policy registration.

Bug= chromium:704091 

Change-Id: Ib14bed7fc3df442aefae4f71f03a75c883150d08
Reviewed-on: https://chromium-review.googlesource.com/704856
Commit-Queue: Denis Kuznetsov <antrim@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Ivan Šandrk <isandrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535388}
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/login/users/fake_chrome_user_manager.h
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/chromeos/policy/user_policy_test_helper.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/policy/cloud/cloud_policy_browsertest.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/chrome/browser/policy/cloud/cloud_policy_manager_browsertest.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/core/common/cloud/cloud_policy_client.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/core/common/cloud/cloud_policy_client.h
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/core/common/cloud/cloud_policy_client_registration_helper.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/core/common/cloud/cloud_policy_client_unittest.cc
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/core/common/cloud/mock_cloud_policy_client.h
[modify] https://crrev.com/4b9250eebac7da0cf2138fceffb5af9855090940/components/policy/proto/device_management_backend.proto

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ee1319b3d1c72f4dfd4d4c3a569cd7c0bfbbc92f

commit ee1319b3d1c72f4dfd4d4c3a569cd7c0bfbbc92f
Author: Denis Kuznetsov <antrim@google.com>
Date: Thu Mar 15 16:09:06 2018

Add default value to Lifetime enum.

Add unnecessary value containing "DEFAULT" in the name just to
make ProtoBestPractices check happy.

Bug:  704091 
Change-Id: I99e62d9d711eef17a783408c0fbe62b115b7ac68
Reviewed-on: https://chromium-review.googlesource.com/951249
Reviewed-by: Pavol Marko <pmarko@chromium.org>
Reviewed-by: Drew Wilson <atwilson@chromium.org>
Commit-Queue: Denis Kuznetsov <antrim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543379}
[modify] https://crrev.com/ee1319b3d1c72f4dfd4d4c3a569cd7c0bfbbc92f/components/policy/proto/device_management_backend.proto

Hi..
Please provide steps if this requires manual verification.

That is just a flag sent in protobuf upon device registration. There is no any user or admin-facing changes, they are only required to detect and remove unused registrations several years down from now.

Thanks for the details, Closing the issue(WAI) for now.