Follow up fix to scheduler alarm memory management: if we decided to have an alarm cleaned up by Signal(), 'this' could get deleted from under Scheduler::CondVarCallbackTimeout::RunAlarm if the user callback relinquished the mutex. (detected by asan)
Follow up fix to scheduler alarm memory management: if we decided to
have an alarm cleaned up by Signal(), 'this' could get deleted from
under Scheduler::CondVarCallbackTimeout::RunAlarm if the user callback
relinquished the mutex.
(detected by asan)


crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp,crowell/modpagespeed_tmp