1703975 - Avoid FOUC with proton infobars

Status: RESOLVED FIXED

(Firefox :: Messaging System, defect, P3)

Description

[Mark Striemer [:mstriemer]]

The proton infobars load common.css and message-bar.css in their shadow DOM. Since this load can happen after the element has been added to the DOM, we could get a flash of unstyled content (FOUC).

This is particularly noticeable in browser_registerProtocolHandler_notification.js where the test immediately triggers an infobar and checks that it has an icon set. This test was updated to wait for the styles to load [1] but we should instead look into avoiding the FOUC and remove the TestUtils.waitForCondition() there.

[1] https://phabricator.services.mozilla.com/D111308

Comment 1

[Mark Striemer [:mstriemer]]

https://phabricator.services.mozilla.com/D111358 also disabled this test in verify mode.

Comment 2

[Punam Dahiya [:pdahiya]]

NI @mstriemer for feedback if this issue still exists or safe to close