Don't try to load user profile images in PhabricatorPeopleQuery if no users have any

Summary:
Fixes T3810. In PhabricatorPeopleQuery, we issue an unnecessary query like this:

  SELECT f.* FROM file f WHERE (f.phid IN ('')) ORDER BY f.id DESC

...if we're loading a user without a profile picture. Filter the file PHIDs before loading them to prevent this.

This doesn't change anything, but saves us a spurious/silly query.

Also makes `PhabricatorPeopleProfileController` use `needProfileImage()`, moving us closer to getting rid of `loadProfileImageURI()` eventually.

Test Plan: Looked at profiles of users with and without profile pictures. Checked query log in DarkConsole.

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran

Maniphest Tasks: T3810

Differential Revision: https://secure.phabricator.com/D6913

src/applications/people/controller/PhabricatorPeopleProfileController.php

@@ -19,6 +19,7 @@ final class PhabricatorPeopleProfileController
     $user = id(new PhabricatorPeopleQuery())
       ->setViewer($viewer)
       ->withUsernames(array($this->username))
+      ->needProfileImage(true)
       ->executeOne();
     if (!$user) {
       return new Aphront404Response();

src/applications/people/query/PhabricatorPeopleQuery.php

@@ -133,11 +133,17 @@ final class PhabricatorPeopleQuery
     }
 
     if ($this->needProfileImage) {
+      $user_profile_file_phids = mpull($users, 'getProfileImagePHID');
+      $user_profile_file_phids = array_filter($user_profile_file_phids);
+      if ($user_profile_file_phids) {
         $files = id(new PhabricatorFileQuery())
           ->setViewer($this->getViewer())
-        ->withPHIDs(mpull($users, 'getProfileImagePHID'))
+          ->withPHIDs($user_profile_file_phids)
           ->execute();
         $files = mpull($files, null, 'getPHID');
+      } else {
+        $files = array();
+      }
       foreach ($users as $user) {
         $image_phid = $user->getProfileImagePHID();
         if (isset($files[$image_phid])) {