We primarily need this because we'd like to stop aggregating Rasterize events on the back-end, as these may have useful nested records, but are still too numerous to show by default on the front-end. The idea is to introduce artificial parent node for top level repeating events.
This also appears to work well with numerous Parse HTML, Send Request and Paint request, slightly improving the density of information presented on main view.
Created attachment 192768 [details]
Comment on attachment 192768 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=192768&action=review
> + coalescedRecord.collapsed = true;
Committed r145727: <http://trac.webkit.org/changeset/145727>