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/1136976Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575324}

components/feature_engagement/README.md

@@ -241,17 +241,18 @@ configuration:
 1.  Add feature to the histogram suffix `IPHFeatures` in:
     `//tools/metrics/histograms/histograms.xml`.
     *   The suffix must match the `base::Feature` `name` member of your feature.
-1.  Add feature to the actions file (actions do not support automatic suffixes):
-    `//tools/metrics/actions/actions.xml`.
+1.  Add feature to the actions file at: `//tools/metrics/actions/actions.xml`.
     *   The suffix must match the `base::Feature` `name` member.
-    *   Use an old example to ensure you configure and describe it correctly.
-    *   For `IPH_MyFunFeature` it would look like this:
-        *   `<action name="InProductHelp.NotifyEvent.IPH_MyFunFeature">`
-        *   `<action name="InProductHelp.NotifyUsedEvent.IPH_MyFunFeature">`
-        *   `<action name="InProductHelp.ShouldTriggerHelpUI.IPH_MyFunFeature">`
-        *   `<action name="InProductHelp.ShouldTriggerHelpUIResult.NotTriggered.IPH_MyFunFeature">`
-        *   `<action name="InProductHelp.ShouldTriggerHelpUIResult.Triggered.IPH_MyFunFeature">`
-        *   `<action name="InProductHelp.ShouldTriggerHelpUIResult.WouldHaveTriggered.IPH_MyFunFeature">`
+    *   Find the `<action-suffix>` entry at the end of the file, where the
+        following `<affected-action>`s are listed:
+        *   `InProductHelp.NotifyEvent.IPH`
+        *   `InProductHelp.NotifyUsedEvent.IPH`
+        *   `InProductHelp.ShouldTriggerHelpUI.IPH`
+        *   `InProductHelp.ShouldTriggerHelpUIResult.NotTriggered.IPH`
+        *   `InProductHelp.ShouldTriggerHelpUIResult.Triggered.IPH`
+        *   `InProductHelp.ShouldTriggerHelpUIResult.WouldHaveTriggered.IPH`
+    *   Add an alphebetically sorted entry to the list of `<suffix>`es like:
+        `<suffix name="MyFunFeature" label="For MyFunFeature feature."/>`
 
 ### Adding a local field trial testing configuration