Implement refreshing logic in Files app.

ui/file_manager/file_manager/foreground/js/file_manager_commands.js

 // Copyright (c) 2012 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.
 
 /**
  * Sets 'hidden' property of a cr.ui.Command instance and dispatches
  * 'hiddenChange' event manually so that associated cr.ui.MenuItem can handle
  * the event.
  * TODO(fukino): Remove this workaround when crbug.com/481941 is fixed.
  *
@@ skipping 1415 matching lines @@
 
 /**
  * Refreshes the currently selected directory.
  */
 CommandHandler.COMMANDS_['refresh'] = /** @type {Command} */ ({
   /**
    * @param {!Event} event Command event.
    * @param {!FileManager} fileManager FileManager to use.
    */
   execute: function(event, fileManager) {
-    // TODO(mtomasz): Implement refreshing.
+    fileManager.directoryModel.rescan(true /* refresh */);
+    fileManager.spinnerController.blink();
   },
   canExecute: function(event, fileManager) {
     var currentDirEntry = fileManager.directoryModel.getCurrentDirEntry();
     var volumeInfo = currentDirEntry &&
         fileManager.volumeManager.getVolumeInfo(currentDirEntry);
     event.canExecute = volumeInfo && !volumeInfo.watchable;
     event.command.setHidden(!event.canExecute ||
         fileManager.directoryModel.getFileListSelection().getCheckSelectMode());
   }
 });