I thought we planned to let Harmony go to beta (but not stable) in M64 to widen the testing pool?  Or did we decide to wait for beta until M65?

Going to Beta requires full launch-review approval. Since there are still a few dialogues remaining, decision was to target M65 Beta/Stable. 

requesting merge for https://chromium-review.googlesource.com/c/chromium/src/+/804623 to m64 directly.

(green tryjobs are in http://crrev.com/c/802604)

Plan is just to land https://chromium-review.googlesource.com/c/chromium/src/+/804623 when this bug has Merge-Approved. Please speak up if there are other steps you think are needed.

Your change meets the bar and is auto-approved for M64. Please go ahead and merge the CL to branch 3282 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), abdulsyed@(Desktop)

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

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/456046b99b3e3a035412c8f85fec5f0f677d3b25

commit 456046b99b3e3a035412c8f85fec5f0f677d3b25
Author: Trent Apted <tapted@chromium.org>
Date: Tue Dec 05 02:59:21 2017

[m64 only] Disable Harmony for M64.

TBR=tapted@chromium.org

Bug:  789770 
Change-Id: I23c372b3f0888d021a8c408ac2250813c16b2acd
Reviewed-on: https://chromium-review.googlesource.com/804623
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/branch-heads/3282@{#21}
Cr-Branched-From: 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840}
[modify] https://crrev.com/456046b99b3e3a035412c8f85fec5f0f677d3b25/ui/base/ui_base_features.cc

Do we need one of these for m65?

I also heard rumours of a 50/50 beta experiment, but landing that config will need some Launch-M-Approved bits flipped in Issue 775847

(the default should probably be disabled in any case).

The CL in #c6 can probably just be cherry-picked again to the m65 branch.

Go ahead and turn it off by default in 65 too (or I can do it). We'll enable the experiment when we get the approvals.