Looking at leaks bot output, I noticed that our biggest leaks (aside from an old well known forms one) happen in LowerDFGToB3::appendOSRExit.
Created attachment 272029 [details]
Looking at this now.
I can repro the leak by just looking at V8Spider/crypto. I'm hunting for the cause now...
This bug is because I didn't know how to call a virtual destructor.
Patch on the way!
Created attachment 272047 [details]
Landed in http://trac.webkit.org/changeset/196996
Confirmed that it's all fixed. Thank you!