Minor refactor of split evaluation in gpu_hist#3889

Merged

RAMitchell merged 3 commits intodmlc:masterfrom RAMitchell:multi-gpu

Nov 13, 2018

+129-193

Commits on Nov 9, 2018

Refactor evaluate split into shard
RAMitchell
committed

Commits on Nov 10, 2018

Use span in evaluate split
RAMitchell
committed

Commits on Nov 12, 2018

Update google tests
RAMitchell
committed