R1:51d8570b3472

Clean up diff view page

Summary: Cleans up some older layouts to new stuffs.

Test Plan: Test with and without a diff ID.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7949