Samsung is still the leader but slipping a little....
Image
Source IDC
http://www.idc.com/getdoc.jsp?containerId=prUS25015114
Samsung sells almost as many phones per quarter as all the other top 4 combined. That's a lot of friggin phones. I doubt Samsung will ever be challenged in this regard, since they can build all their phones in house, but I do see Apple falling to #3 next year and #4 the year after with huawei and Lenovo selling more.
Not that it matters to much to Apple, since they rake in a ton of revenue even with less sales.