Use more smart pointers in Source/WebKit/WebProcess/cocoa/VideoFullscreenManager.mm.
Pull request: https://github.com/WebKit/WebKit/pull/16729
Committed 266935@main (31f34da73845): <https://commits.webkit.org/266935@main> Reviewed commits have been landed. Closing PR #16729 and removing active labels.
<rdar://problem/113945477>