1. Take 1 heap snapshot, wait for the summary view to open.
2. Take another heap snapshot, wait for the summary view to open.
3. Select "Comparison" view.
Note that after frontend reopening if you open the second snapshot and select "Comparison" view the diff will show up.
This is a regression after http://trac.webkit.org/changeset/116218 (early return from WebInspector.HeapProfileHeader.prototype.load)
Created attachment 141184 [details]
Comment on attachment 141184 [details]
Clearing flags on attachment: 141184
Committed r116681: <http://trac.webkit.org/changeset/116681>
All reviewed patches have been landed. Closing bug.