Fix trivial type-check errors in file_manager.

ui/file_manager/file_manager/foreground/js/app_installer.js

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 /**
  * Manage the installation of apps.
  *
  * @param {string} itemId Item id to be installed.
@@ skipping 26 matching lines @@
  * Error message for user cancellation. This must be match with the constant
  * 'kUserCancelledError' in C/B/extensions/webstore_standalone_installer.cc.
  * @type {string}
  * @const
  * @private
  */
 AppInstaller.USER_CANCELLED_ERROR_STR_ = 'User cancelled install';
 
 /**
  * Start an installation.
- * @param {function(boolean, string)} callback Called when the installation is
- *     finished.
+ * @param {function(AppInstaller.Result, string)} callback Called when the
+ *     installation is finished.
  */
 AppInstaller.prototype.install = function(callback) {
   this.callback_ = callback;
   chrome.fileManagerPrivate.installWebstoreItem(
       this.itemId_,
       false,  // Shows installation prompt.
       function() {
         this.onInstallCompleted_(chrome.runtime.lastError);
       }.bind(this));
 };
@@ skipping 11 matching lines @@
   if (error) {
     installerResult =
         error.message == AppInstaller.USER_CANCELLED_ERROR_STR_ ?
         AppInstaller.Result.CANCELLED :
         AppInstaller.Result.ERROR;
     errorMessage = error.message;
   }
   this.callback_(installerResult, errorMessage);
   this.callback_ = null;
 };