Code no longer exists:
Bug 21087 : EventQueue destruction should not happen along with servicemanager destruction
Bug 50104 : PLEvent queue needs priority handling
Bug 55403 : PL_ProcessPendingEvents optimization
Bug 62604 : nsIEventQueue{Service}.idl needs doxygen love
Bug 76075 : nsEventQueueImpl::EventAvailable() should check mElderQueue
Bug 134723: nsEventQueueImpl::~nsEventQueueImpl Getting service @mozilla.org/observer-service;1 on shutdown.
Bug 169247: Investigate allocating PLEvents using a recycler
Bug 245974: plevent should not use GetCurrentProcess on macosx (e.g. for _md_CreateEventQueue) because it doesn't work for non console users
Bug 265544: PL_PostEvent/nsEventQueueImpl::PostEvent error handling is odd
Bug 298499: potential race on idFunc and idFuncClosure in plevent.c
Bug 333390: [@ nsEventQueueServiceImpl::PushThreadEventQueue]

Bugs that I'm not sure are still relevant (or that might be fixed)
Bug 18116 : xpcom/threads: need all-in-one create/push function
Bug 98555 : need to provide a way to push/pop event queues
Bug 292976: Various PLEvents and timers can fire on cached presentations