There is no way to check for the presence of SMIL supplementalTransform() instances, since calling that method implicitly creates it. Split it up into another ensureSupplementalTransform() method, that forces creation and another supplementalTransform() method that simply returns the object, if present.
Pull request: https://github.com/WebKit/WebKit/pull/6294
<rdar://problem/102412148>
Committed 256786@main (e633ef2c414e): <https://commits.webkit.org/256786@main> Reviewed commits have been landed. Closing PR #6294 and removing active labels.