abodenha@ - do we want to merge a fix into m53? It'd probably be disabling PIN all-together or changing the pref name to some temporary non-synced value.

I think this is a reasonable WontFix because PIN is synced.

+ abodenha@ see comment above

PIN unlock is shipping in M54, we shouldn't be seeing it at all in M53 is my understanding. So disabling it in M53 sounds right 

Agreed, since the UI in M53 does not match spec.

I'll upload a patch that disables it on M53.

https://codereview.chromium.org/2280633003

Merge request for m53. The patch is simple, it disables quick unlock entirely. I'm not planning on landing it in master.

If we really want to allow users to play around with quick unlock on m53, we can also back port a few patches which include a flag the user can activate. I don't think this is worthwhile though, seeing as a lot of the experience is broken according to the spec.

[Automated comment] Less than 2 weeks to go before stable on M53, manual review required.

Approving merge to M53 cros.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5a9a22d779166c24ea92d7825d1bf33d1559372e

commit 5a9a22d779166c24ea92d7825d1bf33d1559372e
Author: Jacob Dufault <jdufault@google.com>
Date: Tue Aug 30 20:51:21 2016

Disable pin unlock for m53 only.

See https://codereview.chromium.org/2280633003/.

BUG= 639977 

(cherry picked from commit c897cc67701a2f04cc4554d41a0ad39ff9bd61df)

Review URL: https://codereview.chromium.org/2289393002 .

Cr-Commit-Position: refs/branch-heads/2785@{#793}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[modify] https://crrev.com/5a9a22d779166c24ea92d7825d1bf33d1559372e/chrome/browser/chromeos/login/quick_unlock/pin_storage.cc