Change EuiOutsideClickDetector to use mousedown and mouseup events

[thompsongl]

Summary

#1747 raises the potential need to move away from click events in certain cases (EuiOutsideClickDetector) due to browser vendors moving closer to the event target spec. When mousedown and mouseup target different elements, Chrome 73 now returns the closest common ancestor as its target. Other browsers may soon follow (see below)

References:

• Chromium issue implementing the change
• Chromium issue questioning the change

Checklist

• This was checked in mobile
• This was checked in IE11

- [ ] This was checked in dark mode
- [ ] Any props added have proper autodocs
- [ ] Documentation examples were added

• A changelog entry exists and is marked appropriately

- [ ] This was checked for breaking changes and labeled appropriately

• Jest tests were updated or added to match the most common scenarios

- [ ] This was checked against keyboard-only and screenreader scenarios
- [ ] This required updates to Framer X components

[thompsongl]

@chandlerprall Thoughts on just moving forward with this regardless of what comes from the Chromium issue? They've labelled it WontFix and have indicated that more browsers will move toward this interpretation of the spec

[chandlerprall]

Yeah, I think this is the right thing to do.

[snide]

Will we have to backport this? Potentially to older versions of Kibana?

[chandlerprall]

Will we have to backport this? Potentially to older versions of Kibana?

That seems like a good idea. We'll have to manually backport only the changes to EuiOutsideClickDetector and re-update snapshots as EuiFocusTrap doesn't exist in 6.10.5

[chandlerprall]

LGTM; pulled locally and tested that changes to EuiOutsideClickDetector keep functionality in Chrome 72 and have the same functionality after I updated to Chrome 73.

[thompsongl]

@snide How far back would we need to go?

[snide]

@thompsongl I'll follow up with @chandlerprall. Depending on how bad the issue is we might need to go pretty far back :/

[thompsongl]

I think the original issue describes the most common case (that I can think of) pretty well: highlighting text in a popover or flyout and having the mouseup even happen on a different DOM element than mousedown.

It's hard to know how common that action & result are

[snide]

@thompsongl Given that it's a smaller issue that doesn't break UI (just makes it slightly annoying) I think we should be OK applying it to 6.7.x and 7.0.x kibana. We can monitor github for reports on older versions to see if it's a super large annoyance to people.