Restrict Differential buckets to just ApplicationSearch views

Summary: Ref T9363, If we're in a dashboard panel, only show buckets with data, or a fallback if nothing exists.

Test Plan: Test 'active revisions' panel in a dashboard and in Differential.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T9363

Differential Revision: https://secure.phabricator.com/D17544

src/applications/differential/query/DifferentialRevisionSearchEngine.php

@@ -162,10 +162,13 @@ final class DifferentialRevisionSearchEngine
         $groups = $bucket->newResultGroups($query, $revisions);
 
         foreach ($groups as $group) {
-          $views[] = id(clone $template)
-            ->setHeader($group->getName())
-            ->setNoDataString($group->getNoDataString())
-            ->setRevisions($group->getObjects());
+          // Don't show groups in Dashboard Panels
+          if ($group->getObjects() || !$this->isPanelContext()) {
+            $views[] = id(clone $template)
+              ->setHeader($group->getName())
+              ->setNoDataString($group->getNoDataString())
+              ->setRevisions($group->getObjects());
+          }
         }
       } catch (Exception $ex) {
         $this->addError($ex->getMessage());
@@ -176,6 +179,12 @@ final class DifferentialRevisionSearchEngine
         ->setHandles(array());
     }
 
+    if (!$views) {
+      $views[] = id(new DifferentialRevisionListView())
+        ->setUser($viewer)
+        ->setNoDataString(pht('No revisions found.'));
+    }
+
     $phids = array_mergev(mpull($views, 'getRequiredHandlePHIDs'));
     if ($phids) {
       $handles = id(new PhabricatorHandleQuery())