Bug 151567 reported the regression of r192053(In fact, it's the regression since r192528) It's because tryClose() returned immediately without calling close callback when the page does not have onbeforeunload callback since r192528.
Created attachment 266761 [details] Patch
Comment on attachment 266761 [details] Patch rs=me
Comment on attachment 266761 [details] Patch Clearing flags on attachment: 266761 Committed r193619: <http://trac.webkit.org/changeset/193619>
All reviewed patches have been landed. Closing bug.