Implement PhrictionDocumentQuery

Summary:
Companion for D5284. Move all the query logic to a policy-aware query class. In particular:

  - Currently, anyone can view and edit a project's wiki documents. For callsites using this query class, you must be able to view or edit the project to view or edit its documents.
  - There's some very sketchy logic with the content/document joins. This cleans that up.
  - This cleans up loading projects by moving it inside the query. We need to do this anyway to perform policy checks.

Test Plan: Viewed active/all/updated. Set page size to 2, verified pager works.

Reviewers: AnhNhan, chad

Reviewed By: AnhNhan

CC: aran

Differential Revision: https://secure.phabricator.com/D5285

src/applications/project/query/PhabricatorProjectQuery.php

@@ -6,6 +6,7 @@ final class PhabricatorProjectQuery
   private $ids;
   private $phids;
   private $memberPHIDs;
+  private $slugs;
 
   private $status       = 'status-any';
   const STATUS_ANY      = 'status-any';
@@ -36,6 +37,11 @@ final class PhabricatorProjectQuery
     return $this;
   }
 
+  public function withPhrictionSlugs(array $slugs) {
+    $this->slugs = $slugs;
+    return $this;
+  }
+
   public function needMembers($need_members) {
     $this->needMembers = $need_members;
     return $this;
@@ -155,6 +161,13 @@ final class PhabricatorProjectQuery
         $this->memberPHIDs);
     }
 
+    if ($this->slugs) {
+      $where[] = qsprintf(
+        $conn_r,
+        'phrictionSlug IN (%Ls)',
+        $this->slugs);
+    }
+
     $where[] = $this->buildPagingClause($conn_r);
 
     return $this->formatWhereClause($where);