1894654 - Remove `test.events.async.enabled` preference and use async dispatching for all mouse and touch events through Marionette

Status: NEW

(Core :: DOM: UI Events & Focus Handling, enhancement, P3)

Description

[Edgar Chen [:edgar]]

Currently, we provide a pref, test.events.async.enabled, to specify if the mouse events should be synthesized asynchronously. When the pref is set to true, the mouse event would be all synthesized and dispatched in parent process and then dispatch to content over IPC.

Perhaps we could consider making the utility methods can specify whether this event should be synthesized asynchronously directly, e.g.

EventUtils.synthesizeMouse(element, 1, 1, { type: "mousemove", async: true });

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Edgar, my patch on bug 1968855 should basically do all that already. Why do you think we need another bug for it?

Comment 2

[Edgar Chen [:edgar]]

I leave this open just in case if we need to do anything more to get rid of test.events.async.enabled for synthesizing mouse event, if bug 1968855 covers all things, then we could mark this as a duplicated of bug 1968855.

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+1]]

With my patch I'm not removing all the usages of the test.events.async.enabled preference because we need to support for touch as well. Therefore I've updated only a couple of tests to ensure that the async dispatching is working.

Once both mouse and touch events support the async dispatching we should check again and reduce the usage of this preference as much as possible. Therefore lets wait for bug 1848958 and bug 1797215.

Edgar, should we at some point enable async events by default for those APIs, or should we continue to require an opt-in via the asyncEnabled argument for the methods in EventUtils?

Comment 4

[Edgar Chen [:edgar]]

(In reply to Henrik Skupin [:whimboo][⌚️UTC+2] from comment #3)

Edgar, should we at some point enable async events by default for those APIs, or should we continue to require an opt-in via the asyncEnabled argument for the methods in EventUtils?

Dispatching synthesized event directly in content process is sufficient for most of tests, so we should continue to opt in to asynchronous event dispatching using the asyncEnabled argument, don't need to make it the default behavior.

Comment 5

[Henrik Skupin [:whimboo][⌚️UTC+1]]

We still need to wait at least until all web-platform tests for touch and mouse events work correctly over a couple of weeks.