R1:0c49b396583d

Allow Phriction document history to be viewed

Summary: Simple access to document history.
Test Plan: Looked at document history.
Reviewed By: codeblock
Reviewers: hsb, codeblock, jungejason, tuomaspelkonen, aran
Commenters: hsb
CC: aran, codeblock, hsb
Differential Revision: 658