R1:b21f197a98f2

Fix Diffusion change view header

Summary: See D7162. This was like 99% my fault. Just provide a header; the new ones look pretty reasonable.

Test Plan: Viewed Diffusion change view, no exception.

Reviewers: vrana, chad

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D7183