Add a "Revision status" field to Herald for Differential revisions

Summary: See PHI280. We have a similar field for tasks already, this is generally a reasonable sort of thing to support, and the addition of "draft" states means there are some pretty reasonable use cases.

Test Plan:
  - Wrote a status-based ("status is needs revision") Herald rule.
  - Tested it against a "Needs Revision" revision (passed) and a "Changes Planned" revision (failed).

Reviewers: amckinley

Reviewed By: amckinley

Differential Revision: https://secure.phabricator.com/D18938

src/__phutil_library_map__.php

@@ -590,6 +590,7 @@ phutil_register_library_map(array(
     'DifferentialRevisionStatus' => 'applications/differential/constants/DifferentialRevisionStatus.php',
     'DifferentialRevisionStatusDatasource' => 'applications/differential/typeahead/DifferentialRevisionStatusDatasource.php',
     'DifferentialRevisionStatusFunctionDatasource' => 'applications/differential/typeahead/DifferentialRevisionStatusFunctionDatasource.php',
+    'DifferentialRevisionStatusHeraldField' => 'applications/differential/herald/DifferentialRevisionStatusHeraldField.php',
     'DifferentialRevisionStatusTransaction' => 'applications/differential/xaction/DifferentialRevisionStatusTransaction.php',
     'DifferentialRevisionSummaryHeraldField' => 'applications/differential/herald/DifferentialRevisionSummaryHeraldField.php',
     'DifferentialRevisionSummaryTransaction' => 'applications/differential/xaction/DifferentialRevisionSummaryTransaction.php',
@@ -5701,6 +5702,7 @@ phutil_register_library_map(array(
     'DifferentialRevisionStatus' => 'Phobject',
     'DifferentialRevisionStatusDatasource' => 'PhabricatorTypeaheadDatasource',
     'DifferentialRevisionStatusFunctionDatasource' => 'PhabricatorTypeaheadCompositeDatasource',
+    'DifferentialRevisionStatusHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionStatusTransaction' => 'DifferentialRevisionTransactionType',
     'DifferentialRevisionSummaryHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionSummaryTransaction' => 'DifferentialRevisionTransactionType',

src/applications/differential/herald/DifferentialRevisionStatusHeraldField.php

@@ -0,0 +1,29 @@
+<?php
+
+final class DifferentialRevisionStatusHeraldField
+  extends DifferentialRevisionHeraldField {
+
+  const FIELDCONST = 'revision.status';
+
+  public function getHeraldFieldName() {
+    return pht('Revision status');
+  }
+
+  public function getHeraldFieldValue($object) {
+    return $object->getStatus();
+  }
+
+  protected function getHeraldFieldStandardType() {
+    return self::STANDARD_PHID;
+  }
+
+  protected function getDatasource() {
+    return new DifferentialRevisionStatusDatasource();
+  }
+
+  protected function getDatasourceValueMap() {
+    $map = DifferentialRevisionStatus::getAll();
+    return mpull($map, 'getDisplayName', 'getKey');
+  }
+
+}