Fix cancdn vs canCDN flag

Summary:
Ref T5884. We migrated to add a `canCDN` flag, but the code looks for a `cancdn` flag.

If this fixes the issue, I'll migrate `cancdn` to `canCDN` in the next diff.

Test Plan: Viewed some files, including old files, and saw the cacheability I expected.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5884

Differential Revision: https://secure.phabricator.com/D10264

Author: epriestley

src/applications/files/controller/PhabricatorFileInfoController.php

@@ -213,9 +213,17 @@ private function buildPropertyViews(
         pht('%s px', new PhutilNumber($height)));
     }
 
-    $finfo->addProperty(
-      pht('Cacheable'),
-      $file->getCanCDN() ? pht('Yes') : pht('No'));
+    $is_image = $file->isViewableImage();
+    if ($is_image) {
+      $image_string = pht('Yes');
+      $cache_string = $file->getCanCDN() ? pht('Yes') : pht('No');
+    } else {
+      $image_string = pht('No');
+      $cache_string = pht('Not Applicable');
+    }
+
+    $finfo->addProperty(pht('Viewable Image'), $image_string);
+    $finfo->addProperty(pht('Cacheable'), $cache_string);
 
     $storage_properties = new PHUIPropertyListView();
     $box->addPropertyList($storage_properties, pht('Storage'));

src/applications/files/storage/PhabricatorFile.php

@@ -28,7 +28,7 @@ final class PhabricatorFile extends PhabricatorFileDAO
 
   const METADATA_IMAGE_WIDTH  = 'width';
   const METADATA_IMAGE_HEIGHT = 'height';
-  const METADATA_CAN_CDN = 'cancdn';
+  const METADATA_CAN_CDN = 'canCDN';
 
   protected $name;
   protected $mimeType;
@@ -848,6 +848,12 @@ public function getCanCDN() {
     if (!$this->isViewableImage()) {
       return false;
     }
+
+    // TODO: Migrate away this old constant and remove this check.
+    if (idx($this->metadata, 'cancdn')) {
+      return true;
+    }
+
     return idx($this->metadata, self::METADATA_CAN_CDN);
   }