After loading and closing http://wikitravel.org/en/Main_Page I see 60 StructureIDs leaked, 5 of which are the ones allocated by JSGlobalData. I will post allocation backtraces for them.
Created attachment 24268 [details] Stack traces of leaking allocations Lots of the things leaking are things that are likely to be extended by a JS framework, like StructureIDs created in ObjectPrototype and static function slots in ArrayPrototype. There are also a lot of generic puts on arrays that create leaking StructureIDs.
One particular leak has been spun off as bug 21533.
Created attachment 24291 [details] Somewhat evil fix This fixes the bug, as well as all other StructureID leaks I could find. It is a bit evil, because it is a default argument on a virtual method, and subclasses won't pass it back down to the base class implementation in JSObject. I will probably add an extra default bool argument to make sure people deal with it.
Comment on attachment 24291 [details] Somewhat evil fix Oops, that fix was meant for bug 21533, but I have a new one to post there.
This was fixed by r37508, the fix for bug 21533.