[purity] Add pure frontend functions
[purity] Add pure frontend functions

Reviewed By: ngorogiannis

Differential Revision: D19428097

fbshipit-source-id: d91502039

facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer