Add viewPolicy and attachedToObjectPHID to PhabricatorFile

Summary:
Ref T603. Principally, I want to implement the rule "when you upload a file to an object, users must be able to see the object in order to see the file", since I think this is strongly in line with user expectation. For example, if you attach a file to a Conpherence, it should only be visible to members of that thread.

This adds storage for policies, but doesn't do anything interesting with it yet.

Test Plan: Ran `bin/storage upgrade`.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7175

resources/sql/patches/20130929.filepolicy.sql

@@ -0,0 +1,5 @@
+ALTER TABLE {$NAMESPACE}_file.file
+  ADD viewPolicy VARCHAR(64) NOT NULL COLLATE utf8_bin;
+
+UPDATE {$NAMESPACE}_file.file
+  SET viewPolicy = 'users' WHERE viewPolicy = '';

src/applications/files/storage/PhabricatorFile.php

@@ -30,6 +30,7 @@ final class PhabricatorFile extends PhabricatorFileDAO
 
   protected $ttl;
   protected $isExplicitUpload = 1;
+  protected $viewPolicy = PhabricatorPolicies::POLICY_USER;
 
   private $objects = self::ATTACHABLE;
   private $objectPHIDs = self::ATTACHABLE;

src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php

@@ -1648,6 +1648,10 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type' => 'sql',
         'name' => $this->getPatchPath('20130927.audiomacro.sql'),
       ),
+      '20130929.filepolicy.sql' => array(
+        'type' => 'sql',
+        'name' => $this->getPatchPath('20130929.filepolicy.sql'),
+      ),
     );
   }
 }