The MediaPlayerPrivateWebM player is disabled for the test runner [1] As such, we are never testing the new WebM player. [1] https://searchfox.org/wubkat/rev/f20a3ce20e867a081396437e684de72bf8d52320/Tools/WebKitTestRunner/TestController.cpp#1073
<rdar://problem/115928967>
Pull request: https://github.com/WebKit/WebKit/pull/18118
Committed 268393@main (cf2e0687353f): <https://commits.webkit.org/268393@main> Reviewed commits have been landed. Closing PR #18118 and removing active labels.