Content type checks are done in GStreamerRegistryScanner::isContentTypeSupported() or MediaPlayerPrivateGStreamerMSE::supportsType(). The extraneous MediaPlayerPrivateGStreamer::extendedSupportsType() method is not implemented and should be removed, like done for other ports in r157834.
Pull request: https://github.com/WebKit/WebKit/pull/6303
Committed 256489@main (a12a0c36a046): <https://commits.webkit.org/256489@main> Reviewed commits have been landed. Closing PR #6303 and removing active labels.