We have an optimization in Node.replaceChild() to avoid doing any work when the reference child and the new child are the same node. This optimization is not spec-compliant:
This is an issue because it is observable via Mutation observers / listeners or DOM ranges.
Created attachment 285713 [details]
Comment on attachment 285713 [details]
Clearing flags on attachment: 285713
Committed r204326: <http://trac.webkit.org/changeset/204326>
All reviewed patches have been landed. Closing bug.