Bug 260392

Summary: Apply paint containment via 'mediaControl.css' control stylesheet
Product: WebKit Reporter: Ahmad Saleem <ahmad.saleem792>
Component: MediaAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: destra, eric.carlson, jer.noble, karlcow, webkit-bug-importer
Priority: P2 Keywords: BrowserCompat, InRadar, WPTImpact
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

Description Ahmad Saleem 2023-08-18 09:45:25 PDT 
Hi Team,

This is another Blink merge:

Blink Commit: https://chromium-review.googlesource.com/c/chromium/src/+/4349736

WPT Test Case Live Link: http://wpt.live/webvtt/rendering/cues-with-video/processing-model/evil/non-standard-pseudo-elements.html

Just wanted to raise so we can fix it.

Adding 'BrowserCompat' since only Safari is failing the test case.

If there is alternative way to fix this, happy to take inputs and someone can take it up as well.

Thanks!
Comment 1 Radar WebKit Bug Importer 2023-08-25 09:46:19 PDT 
<rdar://problem/114456301>
Comment 2 Ahmad Saleem 2024-03-10 05:58:10 PDT 
These were additionals:

audio::-webkit-media-controls,
video::-webkit-media-controls {
    contain: paint !important;
}
video::-webkit-media-text-track-container {
    contain: paint !important;
    position: relative !important;
}

______

Here - https://searchfox.org/wubkat/rev/93c3eb8ac99a6b6e3894deaf14e5d38304898b48/Source/WebCore/css/mediaControls.css#30

I think we have to add:

contain: paint !important;

and good to change it to make exclusive to `audio` and `video`.

and for `-webkit-media-text-track-container`, we have it in `mediaControls.css` and `text-tracks.css` and both of them have multiple duplicate rules, which is bug 268269.