As far as I can tell, EchoIteratorDecorator is functionally identical to
IteratorDecorator from includes/libs/iterators/ in core, so why have a
separate copy? (EchoIteratorDecorator does pass through the return value
of next() or rewind(), if any, but there shouldn't be any per the
Iterator interface.)
Change-Id: Ic763ec19c15f67d9c9b42ebffb88c52b9056ed22
The new locateUsersWatchingTitle implementation could end up returning
thousands of users, currently on enwiki there are 25 titles with more
than 10k subscribed users and aprox 550 titles with more than 1k subscribed
users.
This switches the user collection to an iterator based implementation so that
we no longer need to have the entire users list at any one time.
Change-Id: I3d3fa9328f348bb48682d3658622952ce82d3925
