Augmented DifferentailDependsOnFieldSpecification to expose its data over conduit

Summary: Implmented conduit methods from base class in DifferentialDependsOnFieldSpecification

Test Plan: Created two test diffs, made one of them dependent on another. Then checked the dependency over conduit interface for differential.query. Dependency is shown but in terms of PHIDs

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5238

src/applications/differential/field/specification/DifferentialDependsOnFieldSpecification.php

@@ -35,4 +35,16 @@ final class DifferentialDependsOnFieldSpecification
       PhabricatorEdgeConfig::TYPE_DREV_DEPENDS_ON_DREV);
   }
 
+  public function shouldAppearOnConduitView() {
+    return true;
+  }
+
+  public function getValueForConduit() {
+    return $this->getDependentRevisionPHIDs();
+  }
+
+  public function getKeyForConduit() {
+    return 'phabricator:depends-on';
+  }
+
 }