Modernize "task priority" datasource

Summary: Ref T4420.

Test Plan:
  - Used typeahead in Herald rules.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4420

Differential Revision: https://secure.phabricator.com/D9877

src/__phutil_library_map__.php

@@ -944,6 +944,7 @@ phutil_register_library_map(array(
     'ManiphestTaskMailReceiver' => 'applications/maniphest/mail/ManiphestTaskMailReceiver.php',
     'ManiphestTaskOwner' => 'applications/maniphest/constants/ManiphestTaskOwner.php',
     'ManiphestTaskPriority' => 'applications/maniphest/constants/ManiphestTaskPriority.php',
+    'ManiphestTaskPriorityDatasource' => 'applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php',
     'ManiphestTaskProject' => 'applications/maniphest/storage/ManiphestTaskProject.php',
     'ManiphestTaskQuery' => 'applications/maniphest/query/ManiphestTaskQuery.php',
     'ManiphestTaskResultListView' => 'applications/maniphest/view/ManiphestTaskResultListView.php',
@@ -3724,6 +3725,7 @@ phutil_register_library_map(array(
     'ManiphestTaskMailReceiver' => 'PhabricatorObjectMailReceiver',
     'ManiphestTaskOwner' => 'ManiphestConstants',
     'ManiphestTaskPriority' => 'ManiphestConstants',
+    'ManiphestTaskPriorityDatasource' => 'PhabricatorTypeaheadDatasource',
     'ManiphestTaskProject' => 'ManiphestDAO',
     'ManiphestTaskQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'ManiphestTaskResultListView' => 'ManiphestView',

src/applications/herald/controller/HeraldRuleController.php

@@ -591,6 +591,7 @@ final class HeraldRuleController extends HeraldController {
     $sources = array(
       'repository' => new DiffusionRepositoryDatasource(),
       'legaldocuments' => new LegalpadDocumentDatasource(),
+      'taskpriority' => new ManiphestTaskPriorityDatasource(),
     );
 
     $sources = mpull($sources, 'getDatasourceURI');
@@ -601,7 +602,6 @@ final class HeraldRuleController extends HeraldController {
       'project'       => '/typeahead/common/projects/',
       'userorproject' => '/typeahead/common/accountsorprojects/',
       'buildplan'     => '/typeahead/common/buildplans/',
-      'taskpriority'  => '/typeahead/common/taskpriority/',
       'arcanistprojects' => '/typeahead/common/arcanistprojects/',
     );
 

src/applications/maniphest/typeahead/ManiphestTaskPriorityDatasource.php

@@ -0,0 +1,31 @@
+<?php
+
+final class ManiphestTaskPriorityDatasource
+  extends PhabricatorTypeaheadDatasource {
+
+  public function getPlaceholderText() {
+    return pht('Type a task priority name...');
+  }
+
+  public function getDatasourceApplicationClass() {
+    return 'PhabricatorApplicationManiphest';
+  }
+
+  public function loadResults() {
+    $viewer = $this->getViewer();
+    $raw_query = $this->getRawQuery();
+
+    $results = array();
+
+    $priority_map = ManiphestTaskPriority::getTaskPriorityMap();
+    foreach ($priority_map as $value => $name) {
+      // NOTE: $value is not a phid but is unique. This'll work.
+      $results[] = id(new PhabricatorTypeaheadResult())
+        ->setPHID($value)
+        ->setName($name);
+    }
+
+    return $results;
+  }
+
+}

src/applications/typeahead/controller/PhabricatorTypeaheadCommonDatasourceController.php

@@ -33,7 +33,6 @@ final class PhabricatorTypeaheadCommonDatasourceController
     $need_symbols = false;
     $need_jump_objects = false;
     $need_build_plans = false;
-    $need_task_priority = false;
     switch ($this->type) {
       case 'mainsearch':
         $need_users = true;
@@ -84,9 +83,6 @@ final class PhabricatorTypeaheadCommonDatasourceController
       case 'buildplans':
         $need_build_plans = true;
         break;
-      case 'taskpriority':
-        $need_task_priority = true;
-        break;
     }
 
     $results = array();
@@ -225,16 +221,6 @@ final class PhabricatorTypeaheadCommonDatasourceController
       }
     }
 
-    if ($need_task_priority) {
-      $priority_map = ManiphestTaskPriority::getTaskPriorityMap();
-      foreach ($priority_map as $value => $name) {
-        // NOTE: $value is not a phid but is unique. This'll work.
-        $results[] = id(new PhabricatorTypeaheadResult())
-          ->setPHID($value)
-          ->setName($name);
-      }
-    }
-
     if ($need_projs) {
       $projs = id(new PhabricatorProjectQuery())
         ->setViewer($viewer)