The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c5c3c8cd1e92fbf4db57e5ddcc2467a4898b113a

commit c5c3c8cd1e92fbf4db57e5ddcc2467a4898b113a
Author: Tommy Nyquist <nyquist@chromium.org>
Date: Mon Jul 16 17:23:36 2018

Cleanup user actions for in-product help

Currently whenever we add a new in-product help feature, the developer
have to add six distinct <action> entries, which makes it easy to
overlook something. Also, these actions are typically copy-pasted from
an old entry, so they do not typically provide any good documentation
for the particular in-product help feature either.

This CL uses the new functionality introduced in
https://chromium-review.googlesource.com/c/chromium/src/+/1015293
which fixes the fan-out for user actions, making them usable for
chromium.

For all known in-product help entries, this CL moves them to the suffix
list at the bottom of the file. This means that the action suffix list
will be defined for a few extra, since not all of them was in use for
the user actions that have already been moved to the new system.

BUG= 835454 

Change-Id: I72847cda991413e85c6b6e990af1f2e9e0f0cd8e
Reviewed-on: https://chromium-review.googlesource.com/1136976
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575324}
[modify] https://crrev.com/c5c3c8cd1e92fbf4db57e5ddcc2467a4898b113a/components/feature_engagement/README.md
[modify] https://crrev.com/c5c3c8cd1e92fbf4db57e5ddcc2467a4898b113a/tools/metrics/actions/actions.xml

asvitkine: Should the action suffixes list be moved to a separate file and OWNERS policy, or should it be kept where it is right now?

I think the changes to these is low-traffic enough that it's fine to keep as-is. Moving them out adds complexity which is not warranted given the low traffic, imo.

SGTM!