Provide revision parent/child edges in edge.search, and more information in differential.revision.search

Summary: See PHI195. This bulks out these API methods since all the requests are pretty straightforward.

Test Plan: Ran `edge.search` and `differential.revision.search`.

Reviewers: amckinley

Reviewed By: amckinley

Differential Revision: https://secure.phabricator.com/D18762

src/applications/differential/edge/DifferentialRevisionDependedOnByRevisionEdgeType.php

@@ -13,6 +13,20 @@ final class DifferentialRevisionDependedOnByRevisionEdgeType
     return true;
   }
 
+  public function getConduitKey() {
+    return 'revision.child';
+  }
+
+  public function getConduitName() {
+    return pht('Revision Has Child');
+  }
+
+  public function getConduitDescription() {
+    return pht(
+      'The source revision makes changes required by the destination '.
+      'revision.');
+  }
+
   public function getTransactionAddString(
     $actor,
     $add_count,

src/applications/differential/edge/DifferentialRevisionDependsOnRevisionEdgeType.php

@@ -17,6 +17,19 @@ final class DifferentialRevisionDependsOnRevisionEdgeType
     return true;
   }
 
+  public function getConduitKey() {
+    return 'revision.parent';
+  }
+
+  public function getConduitName() {
+    return pht('Revision Has Parent');
+  }
+
+  public function getConduitDescription() {
+    return pht(
+      'The source revision depends on changes in the destination revision.');
+  }
+
   public function getTransactionAddString(
     $actor,
     $add_count,

src/applications/differential/storage/DifferentialRevision.php

@@ -986,6 +986,18 @@ final class DifferentialRevision extends DifferentialDAO
         ->setKey('status')
         ->setType('map<string, wild>')
         ->setDescription(pht('Information about revision status.')),
+      id(new PhabricatorConduitSearchFieldSpecification())
+        ->setKey('repositoryPHID')
+        ->setType('phid?')
+        ->setDescription(pht('Revision repository PHID.')),
+      id(new PhabricatorConduitSearchFieldSpecification())
+        ->setKey('diffPHID')
+        ->setType('phid')
+        ->setDescription(pht('Active diff PHID.')),
+      id(new PhabricatorConduitSearchFieldSpecification())
+        ->setKey('summary')
+        ->setType('string')
+        ->setDescription(pht('Revision summary.')),
     );
   }
 
@@ -1002,6 +1014,9 @@ final class DifferentialRevision extends DifferentialDAO
       'title' => $this->getTitle(),
       'authorPHID' => $this->getAuthorPHID(),
       'status' => $status_info,
+      'repositoryPHID' => $this->getRepositoryPHID(),
+      'diffPHID' => $this->getActiveDiffPHID(),
+      'summary' => $this->getSummary(),
     );
   }