Allow objects to specify custom policy unlocking behavior, and tasks to have owners unlocked

Summary: Depends on D20256. Ref T13249. See PHI1115. This primarily makes `bin/policy unlock --owner epriestley T123` work. This is important for "Edit Locked" tasks, since changing the edit policy doesn't really do anything.

Test Plan: Hard-locked a task as "alice", reassigned it to myself with `bin/policy unlock --owner epriestley`.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13249

Differential Revision: https://secure.phabricator.com/D20257

src/__phutil_library_map__.php

···
     'ManiphestTaskTitleTransaction' => 'applications/maniphest/xaction/ManiphestTaskTitleTransaction.php',
     'ManiphestTaskTransactionType' => 'applications/maniphest/xaction/ManiphestTaskTransactionType.php',
     'ManiphestTaskUnblockTransaction' => 'applications/maniphest/xaction/ManiphestTaskUnblockTransaction.php',
+    'ManiphestTaskUnlockEngine' => 'applications/maniphest/engine/ManiphestTaskUnlockEngine.php',
     'ManiphestTransaction' => 'applications/maniphest/storage/ManiphestTransaction.php',
     'ManiphestTransactionComment' => 'applications/maniphest/storage/ManiphestTransactionComment.php',
     'ManiphestTransactionEditor' => 'applications/maniphest/editor/ManiphestTransactionEditor.php',
···
     'PhabricatorUnitsTestCase' => 'view/__tests__/PhabricatorUnitsTestCase.php',
     'PhabricatorUnknownContentSource' => 'infrastructure/contentsource/PhabricatorUnknownContentSource.php',
     'PhabricatorUnlockEngine' => 'applications/system/engine/PhabricatorUnlockEngine.php',
+    'PhabricatorUnlockableInterface' => 'applications/system/interface/PhabricatorUnlockableInterface.php',
     'PhabricatorUnsubscribedFromObjectEdgeType' => 'applications/transactions/edges/PhabricatorUnsubscribedFromObjectEdgeType.php',
     'PhabricatorUser' => 'applications/people/storage/PhabricatorUser.php',
     'PhabricatorUserApproveTransaction' => 'applications/people/xaction/PhabricatorUserApproveTransaction.php',
···
       'PhabricatorEditEngineLockableInterface',
       'PhabricatorEditEngineMFAInterface',
       'PhabricatorPolicyCodexInterface',
+      'PhabricatorUnlockableInterface',
     ),
     'ManiphestTaskAssignHeraldAction' => 'HeraldAction',
     'ManiphestTaskAssignOtherHeraldAction' => 'ManiphestTaskAssignHeraldAction',
···
     'ManiphestTaskTitleTransaction' => 'ManiphestTaskTransactionType',
     'ManiphestTaskTransactionType' => 'PhabricatorModularTransactionType',
     'ManiphestTaskUnblockTransaction' => 'ManiphestTaskTransactionType',
+    'ManiphestTaskUnlockEngine' => 'PhabricatorUnlockEngine',
     'ManiphestTransaction' => 'PhabricatorModularTransaction',
     'ManiphestTransactionComment' => 'PhabricatorApplicationTransactionComment',
     'ManiphestTransactionEditor' => 'PhabricatorApplicationTransactionEditor',

src/applications/maniphest/engine/ManiphestTaskUnlockEngine.php

···
+<?php
+
+final class ManiphestTaskUnlockEngine
+  extends PhabricatorUnlockEngine {
+
+  public function newUnlockOwnerTransactions($object, $user) {
+    return array(
+      $this->newTransaction($object)
+        ->setTransactionType(ManiphestTaskOwnerTransaction::TRANSACTIONTYPE)
+        ->setNewValue($user->getPHID()),
+    );
+  }
+
+}

src/applications/maniphest/storage/ManiphestTask.php

···
     PhabricatorEditEngineSubtypeInterface,
     PhabricatorEditEngineLockableInterface,
     PhabricatorEditEngineMFAInterface,
-    PhabricatorPolicyCodexInterface {
+    PhabricatorPolicyCodexInterface,
+    PhabricatorUnlockableInterface {
 
   const MARKUP_FIELD_DESCRIPTION = 'markup:desc';
 
···
 
   public function newPolicyCodex() {
     return new ManiphestTaskPolicyCodex();
+  }
+
+
+/* -(  PhabricatorUnlockableInterface  )------------------------------------- */
+
+
+  public function newUnlockEngine() {
+    return new ManiphestTaskUnlockEngine();
   }
 
 }

src/applications/system/engine/PhabricatorUnlockEngine.php

···
           'PhabricatorApplicationTransactionInterface'));
     }
 
-    return new PhabricatorDefaultUnlockEngine();
+    if ($object instanceof PhabricatorUnlockableInterface) {
+      $engine = $object->newUnlockEngine();
+    } else {
+      $engine = new PhabricatorDefaultUnlockEngine();
+    }
+
+    return $engine;
   }
 
   public function newUnlockViewTransactions($object, $user) {

src/applications/system/interface/PhabricatorUnlockableInterface.php

···
+<?php
+
+interface PhabricatorUnlockableInterface {
+
+  public function newUnlockEngine();
+
+}
+
+// TEMPLATE IMPLEMENTATION /////////////////////////////////////////////////////
+
+/* -(  PhabricatorUnlockableInterface  )------------------------------------- */
+/*
+
+  public function newUnlockEngine() {
+    return new <<<...>>>UnlockEngine();
+  }
+
+*/