This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
"Run element upgrade algorithm with TREE and DEFINITION as arguments" If there are multiple registrations happening at the same time, we'll need to walk the DOM multiple times. We should consider bulk registration, where the upgrades are happening for multiple elements.
I walked around this problem, and concluded that implementations are free to use better/faster algorithms and data structures that are equivalent to the spec algorithm. No special spec wording is necessary.