Add a flag column to Differential revision lists

Summary:
Put a flag icon to the left of each flagged revision in the
Differential summary tables. Flag is colored correctly and when hovered
reveals the note in a tooltip.

As epriestley specifically notes that the Flagged Revisions table should
only be shown when a user is looking at their own revisions, maybe this
ought to be limited by what controller is using this view, or something.

Test Plan:
View Differential main page. Check that flags appear
correctly if some revisions are flagged.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin, avivey

Maniphest Tasks: T1557

Differential Revision: https://secure.phabricator.com/D3125

src/applications/differential/view/DifferentialRevisionListView.php

@@ -67,6 +67,11 @@ final class DifferentialRevisionListView extends AphrontView {
       throw new Exception("Call setUser() before render()!");
     }
 
+    $flags = id(new PhabricatorFlagQuery())
+      ->withObjectPHIDs(mpull($this->revisions, 'getPHID'))
+      ->execute();
+    $flagged = mpull($flags, null, 'getObjectPHID');
+
     foreach ($this->fields as $field) {
       $field->setUser($this->user);
       $field->setHandles($this->handles);
@@ -74,15 +79,28 @@ final class DifferentialRevisionListView extends AphrontView {
 
     $rows = array();
     foreach ($this->revisions as $revision) {
-      $row = array();
+      $phid = $revision->getPHID();
+      $flag = '';
+      if (isset($flagged[$phid])) {
+        $class = PhabricatorFlagColor::getCSSClass($flagged[$phid]->getColor());
+        $note = $flagged[$phid]->getNote();
+        $flag = phutil_render_tag(
+          'div',
+          array(
+            'class' => 'phabricator-flag-icon '.$class,
+            'title' => $note,
+          ),
+          '');
+      }
+      $row = array($flag);
       foreach ($this->fields as $field) {
         $row[] = $field->renderValueForRevisionList($revision);
       }
       $rows[] = $row;
     }
 
-    $headers = array();
-    $classes = array();
+    $headers = array('');
+    $classes = array('');
     foreach ($this->fields as $field) {
       $headers[] = $field->renderHeaderForRevisionList();
       $classes[] = $field->getColumnClassForRevisionList();