Explicitly track inline comment reply threading

Summary:
Ref T1460. Track and store which comments are threaded replies to other comments, vs merely appearing on the same lines.

This doesn't actually write `hasReplies` yet, since that needs to happen when we un-draft comments on submission.

Test Plan: Made inline comments in Differential and Diffusion, including replies. Replies were marked as "Is Reply".

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T1460

Differential Revision: https://secure.phabricator.com/D12017

src/applications/differential/query/DifferentialInlineCommentQuery.php

@@ -9,6 +9,7 @@ final class DifferentialInlineCommentQuery
   private $revisionIDs;
   private $notDraft;
   private $ids;
+  private $phids;
   private $commentIDs;
 
   private $viewerAndChangesetIDs;
@@ -30,6 +31,11 @@ final class DifferentialInlineCommentQuery
     return $this;
   }
 
+  public function withPHIDs(array $phids) {
+    $this->phids = $phids;
+    return $this;
+  }
+
   public function withViewerAndChangesetIDs($author_phid, array $ids) {
     $this->viewerAndChangesetIDs = array($author_phid, $ids);
     return $this;
@@ -111,6 +117,13 @@ final class DifferentialInlineCommentQuery
         $this->ids);
     }
 
+    if ($this->phids !== null) {
+      $where[] = qsprintf(
+        $conn_r,
+        'phid IN (%Ls)',
+        $this->phids);
+    }
+
     if ($this->viewerAndChangesetIDs) {
       list($phid, $ids) = $this->viewerAndChangesetIDs;
       $where[] = qsprintf(