I hit an assertion in RefCountedLeakCounter::cancelMessageSuppression() twice today when closing a Safari window. I cannot reliably reproduce it, though. ASSERTION FAILED: leakMessageSuppressionReasons->contains(reason)
I see what's wrong. I forgot to add some code to initWithCoder: that is in initWithFrame:. I'll fix it now.
Created attachment 23574 [details] patch
Comment on attachment 23574 [details] patch r=me
http://trac.webkit.org/changeset/36668