Fix changeset loading issue for "Download Raw Diff" in Differential

Summary: Fixes T5309. Modernize this callsite to use ChangesetQuery and pick up attached objects.

Test Plan: Clicked "Download Raw Diff" in Differential.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T5309

Differential Revision: https://secure.phabricator.com/D9461

src/applications/differential/controller/DifferentialRevisionViewController.php

@@ -673,16 +673,15 @@ final class DifferentialRevisionViewController extends DifferentialController {
     DifferentialDiff $diff_vs = null,
     PhabricatorRepository $repository = null) {
 
-    $load_ids = array();
+    $load_diffs = array($target);
     if ($diff_vs) {
-      $load_ids[] = $diff_vs->getID();
+      $load_diffs[] = $diff_vs;
     }
-    $load_ids[] = $target->getID();
 
-    $raw_changesets = id(new DifferentialChangeset())
-      ->loadAllWhere(
-        'diffID IN (%Ld)',
-        $load_ids);
+    $raw_changesets = id(new DifferentialChangesetQuery())
+      ->setViewer($this->getRequest()->getUser())
+      ->withDiffs($load_diffs)
+      ->execute();
     $changeset_groups = mgroup($raw_changesets, 'getDiffID');
 
     $changesets = idx($changeset_groups, $target->getID(), array());