Added typedefs for using the allocator with random sorters.
Added typedefs for using the allocator with random sorters.

Review: https://reviews.apache.org/r/67373/

andschwa/mesos,dforsyth/mesos,reneploetz/mesos,jpeach/mesos,gsantovena/mesos,andschwa/mesos,dforsyth/mesos,andschwa/mesos,abudnik/mesos,andschwa/mesos,jpeach/mesos,kaysoky/mesos,gsantovena/mesos,andschwa/mesos,andschwa/mesos,gsantovena/mesos,kaysoky/mesos,jpeach/mesos,gsantovena/mesos,jpeach/mesos,abudnik/mesos,reneploetz/mesos,reneploetz/mesos,Gilbert88/mesos,Gilbert88/mesos,kaysoky/mesos,Gilbert88/mesos,abudnik/mesos,kaysoky/mesos,chhsia0/mesos,andschwa/mesos,reneploetz/mesos,jpeach/mesos,gsantovena/mesos,dforsyth/mesos,abudnik/mesos,jpeach/mesos,Gilbert88/mesos,abudnik/mesos,chhsia0/mesos,reneploetz/mesos,kaysoky/mesos,Gilbert88/mesos,chhsia0/mesos,abudnik/mesos,reneploetz/mesos,kaysoky/mesos,dforsyth/mesos,abudnik/mesos,Gilbert88/mesos,reneploetz/mesos,chhsia0/mesos,chhsia0/mesos,dforsyth/mesos,gsantovena/mesos,gsantovena/mesos,chhsia0/mesos,kaysoky/mesos,Gilbert88/mesos,dforsyth/mesos,dforsyth/mesos,jpeach/mesos,chhsia0/mesos