R1:ab5e019b3d97

Pass user to DifferentialRevisionDetailRenderer

Summary: I know that this code would be replaced by something else but until then...

Test Plan: Used it in our renderer.

Reviewers: epriestley, edward

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5165