Support drag-and-drop to set cover images on workboard cards

Summary: This was slightly more complex than I believed, but not too terrible.

Test Plan:
{F1096126}

  - Also used some normal file uploaders to make sure I didn't break that.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D15202

src/applications/project/controller/PhabricatorProjectController.php

@@ -147,4 +147,53 @@ abstract class PhabricatorProjectController extends PhabricatorController {
     return $this;
   }
 
+  protected function newCardResponse($board_phid, $object_phid) {
+    $viewer = $this->getViewer();
+
+    $project = id(new PhabricatorProjectQuery())
+      ->setViewer($viewer)
+      ->withPHIDs(array($board_phid))
+      ->executeOne();
+    if (!$project) {
+      return new Aphront404Response();
+    }
+
+    // Reload the object so it reflects edits which have been applied.
+    $object = id(new ManiphestTaskQuery())
+      ->setViewer($viewer)
+      ->withPHIDs(array($object_phid))
+      ->needProjectPHIDs(true)
+      ->executeOne();
+    if (!$object) {
+      return new Aphront404Response();
+    }
+
+    $except_phids = array($board_phid);
+    if ($project->getHasSubprojects() || $project->getHasMilestones()) {
+      $descendants = id(new PhabricatorProjectQuery())
+        ->setViewer($viewer)
+        ->withAncestorProjectPHIDs($except_phids)
+        ->execute();
+      foreach ($descendants as $descendant) {
+        $except_phids[] = $descendant->getPHID();
+      }
+    }
+
+    $rendering_engine = id(new PhabricatorBoardRenderingEngine())
+      ->setViewer($viewer)
+      ->setObjects(array($object))
+      ->setExcludedProjectPHIDs($except_phids);
+
+    $card = $rendering_engine->renderCard($object->getPHID());
+
+    $item = $card->getItem();
+    $item->addClass('phui-workcard');
+
+    return id(new AphrontAjaxResponse())
+      ->setContent(
+        array(
+          'task' => $item,
+        ));
+  }
+
 }