1794011 - Could css transitions with a delay add their RefreshObserver at the end of the delay?

Status: NEW

(Core :: CSS Transitions and Animations, enhancement)

Description

[Florian Quèze [:florian]]

See this profile of the 300ms opacity transition of the "playing" label under tab names, that starts playing with a 2.7s delay after the media has stopped playing: https://share.firefox.dev/3ClzwkW

In the profile I see refresh driver ticks on the main thread, and composites on the Compositor thread. Could we avoid all these wake-ups by adding the refresh observer only when the delay is over?

Comment 1

[Hiroyuki Ikezoe (:hiro)]

I wonder how much power consumption it reduces in the wild. I mean, how often do we see this kind of positive delay transitions? If we want to avoid the case in our code, triggering the CSS transition in a setTimeout callback would be an easy and reasonable way I think.