Reduce size of PerformanceEntry by leveraging the fact that it is polymorphic.
Created attachment 392149 [details] Patch
Comment on attachment 392149 [details] Patch rs=me
Comment on attachment 392149 [details] Patch Clearing flags on attachment: 392149 Committed r257727: <https://trac.webkit.org/changeset/257727>
All reviewed patches have been landed. Closing bug.
<rdar://problem/59963367>