[webkit-changes] [WebKit/WebKit] bb909a: [Cocoa] ::cue background-color not changed unless ...

[Jer Noble]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: bb909a8331522160a271cc9943fa804d4b1c8a5c
      https://github.com/WebKit/WebKit/commit/bb909a8331522160a271cc9943fa804d4b1c8a5c
  Author: Jer Noble <jer.noble at apple.com>
  Date:   2023-07-11 (Tue, 11 Jul 2023)

  Changed paths:
    A LayoutTests/media/track/track-user-stylesheet-override-expected.txt
    A LayoutTests/media/track/track-user-stylesheet-override.html
    M Source/WebCore/Modules/modern-media-controls/controls/text-tracks.css

  Log Message:
  -----------
  [Cocoa] ::cue background-color not changed unless "allow video to override" unchecked
https://bugs.webkit.org/show_bug.cgi?id=259121
rdar://112100260

Reviewed by Andy Estes.

The `text-tracks.css` UA style sheet sets default styles for VTT cues by setting
a style on `video::cue`. However that has a higher specificity than the styles generated
by the platform, which use `::cue`. This means, in effect, that the system provided
styles (as specified by the user) are ignored unless they are accompanied by a '!important'
rule, which means those rules also cannot be overridden by page provided styles.

Move from `video::cue` to `::cue` in the UA provided styles, allowing both the platform
and the page to override them.

* LayoutTests/media/track/track-user-stylesheet-override-expected.txt: Added.
* LayoutTests/media/track/track-user-stylesheet-override.html: Added.
* Source/WebCore/Modules/modern-media-controls/controls/text-tracks.css:
(::cue):
(::-webkit-media-text-track-display):
(::-webkit-media-text-track-display-backdrop):
(::cue(:future)):
(video::cue): Deleted.
(video::-webkit-media-text-track-display): Deleted.
(video::-webkit-media-text-track-display-backdrop): Deleted.
(video::cue(:future)): Deleted.

Canonical link: https://commits.webkit.org/265975@main