Bug 1805414 will move menu event handling to the DOM.
With that change the current synthetic click behavior of XUL menuitems
breaks. On current central, we rely on nsMenuFrame::HandleEvent not
getting called at all for synthetic clicks, and instead we just fire a
command event synchronously here:
https://searchfox.org/mozilla-central/rev/a0d4f8f112c5c792ae272bf6ce50763ddd23ffa2/dom/xul/nsXULElement.cpp#1071
After my patch the command event is fired properly (potentially
asynchronously too) by the regular menu activation machinery, which is
preferable.
* They fire a command event synchronously (even though on some
platforms like macOS activating a context menu item is async).
* They use a totally different codepath from what a user does.
* They don't deal with native menus, etc.
We have a proper API for this (activateItem) which takes a much more
closer codepath to what users do, requires that the menu is shown, etc.
Use that API instead for testing.
As a benefit, tests now do not need to close the context menu manually
when clicking on a menu item (because we trigger the same code path as
users clicking the menu).
Differential Revision: https://phabricator.services.mozilla.com/D164567
9a53f8dea3