[Cocoa] Video doesn't resize on YouTube.com in theater mode
<rdar://problem/105929105>
Pull request: https://github.com/WebKit/WebKit/pull/13587
Committed 263836@main (95f95436a7cd): <https://commits.webkit.org/263836@main> Reviewed commits have been landed. Closing PR #13587 and removing active labels.
Re-opening for pull request https://github.com/WebKit/WebKit/pull/13621
Committed 263846@main (1c22f6e64ba0): <https://commits.webkit.org/263846@main> Reviewed commits have been landed. Closing PR #13621 and removing active labels.