split WorkerController.call into helper functions
split WorkerController.call into helper functions

Summary: refactoring

Reviewed By: samwgoldman

Differential Revision: D23348094

fbshipit-source-id: 97282b233d276c38df359e73c83f2c22ae605fc0

facebook/flow,mroch/flow,mroch/flow,mroch/flow,facebook/flow,facebook/flow,mroch/flow,mroch/flow,mroch/flow,mroch/flow,facebook/flow,facebook/flow,facebook/flow,facebook/flow