Treat ApplePayButton as a ControlPart and draw it through GraphicsContext::drawControlPart(). Remove the special case for drawing the ApplePayButton as a SystemImage.
<rdar://problem/104850550>
Pull request: https://github.com/WebKit/WebKit/pull/9364
Committed 259652@main (a586299ede2e): <https://commits.webkit.org/259652@main> Reviewed commits have been landed. Closing PR #9364 and removing active labels.