Please list the action items on this bug - it'll be difficult for us to remember exactly what needs to be cleaned up since we won't end up working on this for a while. Thanks!

We definitely have some browser tests to add.

I'm placing this bug number in key TODOs, wherever reviewers have nits.

The biggest issue so far that needs to be resolved in this bug is to only require authentication for enabling Better Together Suite if the Smart Lock user pref is already enabled. 

Ryan, please move that last piece to its own bug. That needs to be done by launch, so it should be considered more urgent than just "cleaning up technical debt." Thanks!

Good point, done:  crbug.com/876436 

stevenjb@ had some comments on https://chromium-review.googlesource.com/c/chromium/src/+/1179377/6/chrome/browser/resources/settings/controls/password_prompt_dialog.js#89 that I will address in the context of this bug.

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