Build fails when ENABLE_MODERN_MEDIA_CONTROLS is disabled, because css/mediaControls.css is not added in WebCore_USER_AGENT_STYLE_SHEETS, since 255715@main.
Pull request: https://github.com/WebKit/WebKit/pull/18014
Committed 268355@main (cd2d810df254): <https://commits.webkit.org/268355@main> Reviewed commits have been landed. Closing PR #18014 and removing active labels.
<rdar://problem/115926477>