Compiling file_manager, part 2: remove all warnings not caused by Object.freeze()-like enums

ui/file_manager/image_loader/image_loader_client.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';
 
 /**
  * Client used to connect to the remote ImageLoader extension. Client class runs
  * in the extension, where the client.js is included (eg. Files.app).
  * It sends remote requests using IPC to the ImageLoader class and forwards
@@ skipping 105 matching lines @@
 };
 
 /**
  * Loads and resizes and image. Use opt_isValid to easily cancel requests
  * which are not valid anymore, which will reduce cpu consumption.
  *
  * @param {string} url Url of the requested image.
  * @param {function} callback Callback used to return response.
  * @param {Object=} opt_options Loader options, such as: scale, maxHeight,
  *     width, height and/or cache.
- * @param {function=} opt_isValid Function returning false in case
+ * @param {function(): boolean=} opt_isValid Function returning false in case
  *     a request is not valid anymore, eg. parent node has been detached.
  * @return {?number} Remote task id or null if loaded from cache.
  */
 ImageLoaderClient.prototype.load = function(
     url, callback, opt_options, opt_isValid) {
   opt_options = opt_options || {};
   opt_isValid = opt_isValid || function() { return true; };
 
   // Record cache usage.
   ImageLoaderClient.recordPercentage('Cache.Usage', this.cache_.getUsage());
@@ skipping 223 matching lines @@
       onError();
       return;
     }
     image.src = result.data;
     onSuccess();
   };
 
   return ImageLoaderClient.getInstance().load(
       url, callback, options, opt_isValid);
 };