Files.app: Fix closure compiler errors.

BUG=NONE
TEST=NONE

Review URL: https://codereview.chromium.org/847453002

Cr-Commit-Position: refs/heads/master@{#310744}

third_party/closure_compiler/externs/file_manager_private.js

@@ -27,12 +27,14 @@ var FileTask;
  *   fileSize: (number|undefined),
  *   lastModifiedTime: (number|undefined),
  *   thumbnailUrl: (string|undefined),
+ *   externalFileUrl: (string|undefined),
  *   imageWidth: (number|undefined),
  *   imageHeight: (number|undefined),
  *   imageRotation: (number|undefined),
  *   isPinned: (boolean|undefined),
  *   isPresent: (boolean|undefined),
  *   isHosted: (boolean|undefined),
+ *   isDirty: (boolean|undefined),
  *   isAvailableOffline: (boolean|undefined),
  *   isAvailableWhenMetered: (boolean|undefined),
  *   customIconUrl: (string|undefined),

ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js

@@ -869,9 +869,9 @@ ExternalProvider.prototype.callApi_ = function() {
 
 /**
  * Converts API metadata to internal format.
- * @param {Object} data Metadata from API call.
- * @param {Entry} entry File entry.
- * @return {Object} Metadata in internal format.
+ * @param {!EntryProperties} data Metadata from API call.
+ * @param {!Entry} entry File entry.
+ * @return {!Object} Metadata in internal format.
  * @private
  */
 ExternalProvider.prototype.convert_ = function(data, entry) {