Revert of base: Remove using:: declaration from version.h header.

chrome/browser/chromeos/login/kiosk_browsertest.cc

 // Copyright (c) 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.
 
 #include <vector>
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/desktop_background/desktop_background_controller_observer.h"
 #include "ash/shell.h"
 #include "base/bind.h"
@@ skipping 536 matching lines @@
 
     LaunchApp(test_app_id(), false);
   }
 
   const extensions::Extension* GetInstalledApp() {
     Profile* app_profile = ProfileManager::GetPrimaryUserProfile();
     return extensions::ExtensionSystem::Get(app_profile)->
         extension_service()->GetInstalledExtension(test_app_id_);
   }
 
-  const base::Version& GetInstalledAppVersion() {
+  const Version& GetInstalledAppVersion() {
     return *GetInstalledApp()->version();
   }
 
   void WaitForAppLaunchWithOptions(bool check_launch_data, bool terminate_app) {
     ExtensionTestMessageListener
         launch_data_check_listener("launchData.isKioskSession = true", false);
 
     // Wait for the Kiosk App to launch.
     content::WindowedNotificationObserver(
         chrome::NOTIFICATION_KIOSK_APP_LAUNCHED,
@@ skipping 1377 matching lines @@
   content::WindowedNotificationObserver(
       chrome::NOTIFICATION_KIOSK_AUTOLAUNCH_WARNING_VISIBLE,
       content::NotificationService::AllSources()).Wait();
 
   // Wait for the wallpaper to load.
   WaitForWallpaper();
   EXPECT_TRUE(wallpaper_loaded());
 }
 
 }  // namespace chromeos