Show file UI box as collapsed in Diffusion

Summary: This UI should have a Collapsed PHUIObjectBoxView.

Test Plan: review a file in sandbox

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D14139

src/applications/diffusion/controller/DiffusionBrowseFileController.php

@@ -337,7 +337,8 @@ final class DiffusionBrowseFileController extends DiffusionBrowseController {
 
     $corpus = id(new PHUIObjectBoxView())
       ->setHeader($header)
-      ->appendChild($corpus);
+      ->appendChild($corpus)
+      ->setCollapsed(true);
 
     return $corpus;
   }