Diffusion - return 404 errors for bad URIs

Summary: Fixes T5646. Makes diffusion a much better user experience. Users now see a 404 exception page when they have a bad URI. Previously, they saw a developer-facing raw exception.

Test Plan: played around in diffusion a bunch. most of these changes were fairly mechanical at the end of the day.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T5646

Differential Revision: https://secure.phabricator.com/D11299

src/applications/diffusion/controller/DiffusionLintDetailsController.php

@@ -2,9 +2,9 @@
 
 final class DiffusionLintDetailsController extends DiffusionController {
 
-  public function processRequest() {
+  protected function processDiffusionRequest(AphrontRequest $request) {
     $limit = 500;
-    $offset = $this->getRequest()->getInt('offset', 0);
+    $offset = $request->getInt('offset', 0);
 
     $drequest = $this->getDiffusionRequest();
     $branch = $drequest->loadBranch();
@@ -70,7 +70,7 @@ final class DiffusionLintDetailsController extends DiffusionController {
       ->setPageSize($limit)
       ->setOffset($offset)
       ->setHasMorePages(count($messages) >= $limit)
-      ->setURI($this->getRequest()->getRequestURI(), 'offset');
+      ->setURI($request->getRequestURI(), 'offset');
 
     $content[] = id(new AphrontPanelView())
       ->setNoBackground(true)