[gh-466] Entity API: Add patch that adds 'uri callback' to file entity

See http://drupal.org/node/1481372#comment-6529650

README.md

@@ -103,6 +103,10 @@ In this example the web root is /Library/WebServer/Documents and Apache runs as
 
      - Fix so that drush pulls in the correct uri parameter. See http://drupal.org/node/1331106
 
+  *  entity/entity.module, entity/modules/callbacks.inc
+
+     - Add 'uri callback' for file entities. See http://drupal.org/node/1481372#comment-6529650
+
   *  workbench_moderation.module
 
      - Fix broken books in workbench_moderation_node_presave(). See http://drupal.org/node/1505060

sites/all/modules/entity/entity.module

@@ -1384,6 +1384,9 @@ function _entity_info_add_metadata(&$entity_info) {
   $entity_info['node']['form callback'] = 'entity_metadata_form_node';
   $entity_info['user']['form callback'] = 'entity_metadata_form_user';
 
+  // URI callbacks.
+  $entity_info['file']['uri callback'] = 'entity_metadata_uri_file';
+
   // View callbacks.
   $entity_info['node']['view callback'] = 'entity_metadata_view_node';
   $entity_info['user']['view callback'] = 'entity_metadata_view_single';

sites/all/modules/entity/modules/callbacks.inc

@@ -946,3 +946,12 @@ function entity_metadata_field_query($entity_type, $property, $value, $limit) {
   $result = $query->execute();
   return !empty($result[$entity_type]) ? array_keys($result[$entity_type]) : array();
 }
+
+/**
+ * Callback so that entity_uri() can generate a uri for file entities.
+ */
+function entity_metadata_uri_file($file) {
+  return array(
+    'path' => file_create_url($file->uri),
+  );
+}