Fixed gear menu navigation using keyboard.

chrome/browser/resources/file_manager/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.
 
 'use strict';
 
 var CommandUtil = {};
 
 /**
  * Extracts root on which command event was dispatched.
@@ skipping 312 matching lines @@
   canExecute: CommandUtil.canExecuteVisibleOnDriveOnly
 };
 
 /**
  * Clears drive cache.
  */
 Commands.driveClearCacheCommand = {
   execute: function() {
     chrome.fileBrowserPrivate.clearDriveCache();
   },
-  canExecute: CommandUtil.canExecuteVisibleOnDriveOnly
+  canExecute: CommandUtil.canExecuteEnabledOnDriveOnly
 };
 
 /**
  * Reload the metadata of the file system from the server
  */
 Commands.driveReloadCommand = {
   execute: function() {
     chrome.fileBrowserPrivate.reloadDrive();
   },
-  canExecute: CommandUtil.canExecuteVisibleOnDriveOnly
+  canExecute: CommandUtil.canExecuteEnabledOnDriveOnly
 };
 
 /**
  * Opens drive.google.com.
  */
 Commands.driveGoToDriveCommand = {
   execute: function() {
     window.open(FileManager.GOOGLE_DRIVE_ROOT, 'drive-root');
   },
   canExecute: CommandUtil.canExecuteVisibleOnDriveOnly
@@ skipping 88 matching lines @@
     fileManager.copyManager_.zipSelection(dirEntry, fileManager.isOnDrive(),
                                           selectionEntries);
   },
   canExecute: function(event, fileManager) {
     var selection = fileManager.getSelection();
     event.canExecute = !fileManager.isOnReadonlyDirectory() &&
         !fileManager.isOnDrive() &&
         selection && selection.totalCount > 0;
   }
 };