[CSS Transitions] display: none - no transitioned event should be fired

HI,

Per the first resolution in the "AnimationEnd events and display: none"
section of [1], we should also do this for transitions. If an element is
made display:none while a transition is in progress, no transitionend event
should be fired for that aborted transition. Chrome, Safari, and IE11
comply with it and they can pass the test [2]. Firefox is also working on
it [3]. (We'd cancel all transitions after setting display:none on the
target element.) However, the spec doesn't mention it much now, so I think
it's better to explain/specify transitions don't run on display:none in the
spec. If possible, I think we should also note what is the expected
behaviour with display:content. Could we get it edited into spec it? Thanks.


[1] https://lists.w3.org/Archives/Public/www-style/2015Apr/0405.html
[2]
https://test.csswg.org/suites/css-transitions-1_dev/nightly-unstable/html/events-007.htm
[3] https://bugzilla.mozilla.org/show_bug.cgi?id=1182856

-- 
Best regards,
Boris Chiou