Fix all type errors in image_loader.

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 69 matching lines @@
 
 /**
  * Sends a message to the Image Loader extension.
  * @param {Object} request Hash array with request data.
  * @param {function(Object)=} opt_callback Response handling callback.
  *     The response is passed as a hash array.
  * @private
  */
 ImageLoaderClient.sendMessage_ = function(request, opt_callback) {
   opt_callback = opt_callback || function(response) {};
-  var sendMessage = chrome.runtime ? chrome.runtime.sendMessage :
-                                     chrome.extension.sendMessage;
-  sendMessage(ImageLoaderClient.EXTENSION_ID, request, opt_callback);
+  chrome.runtime.sendMessage(

[fukino, 2014/10/07 09:52:44]

I think we can use chrome.runtime.sendMessage safely now (since Chrome 26).

+      ImageLoaderClient.EXTENSION_ID, request, opt_callback);
 };
 
 /**
  * Handles a message from the remote image loader and calls the registered
  * callback to pass the response back to the requester.
  *
  * @param {Object} message Response message as a hash array.
  * @private
  */
 ImageLoaderClient.prototype.handleMessage_ = function(message) {
@@ skipping 257 matching lines @@
       onError();
       return;
     }
     image.src = result.data;
     onSuccess();
   };
 
   return ImageLoaderClient.getInstance().load(
       url, callback, options, opt_isValid);
 };