Clean up some more handle callsites

Summary: Ref T7689.

Test Plan:
- Viewed Calendar browse and detail views.
- Went through Differential update workflow.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7689

Differential Revision: https://secure.phabricator.com/D12341

src/applications/differential/controller/DifferentialChangesetViewController.php

@@ -6,8 +6,7 @@ final class DifferentialChangesetViewController extends DifferentialController {
     return true;
   }
 
-  public function processRequest() {
-    $request = $this->getRequest();
+  public function handleRequest(AphrontRequest $request) {
     $viewer = $this->getViewer();
 
     $author_phid = $viewer->getPHID();