Update cached kiosk app crx from usb stick.

chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_APP_MODE_KIOSK_APP_MANAGER_OBSERVER_H_
 #define CHROME_BROWSER_CHROMEOS_APP_MODE_KIOSK_APP_MANAGER_OBSERVER_H_
 
 #include <string>
 
 namespace chromeos {
 
 class KioskAppManagerObserver {
  public:
   // Invoked when the app data is changed or loading state is changed.
   virtual void OnKioskAppDataChanged(const std::string& app_id) {}
 
   // Invoked when failed to load web store data of an app.
   virtual void OnKioskAppDataLoadFailure(const std::string& app_id) {}
 
   // Invoked when the extension is loaded in cache.
   virtual void OnKioskExtensionLoadedInCache(const std::string& app_id) {}
 
   // Invoked when the extension download fails.
   virtual void OnKioskExtensionDownloadFailed(const std::string& app_id) {}
 
   // Invoked when the Kiosk Apps configuration changes.
   virtual void OnKioskAppsSettingsChanged() {}
 
+  // Invoked when kiosk app cache is updated for |app_id|.
+  virtual void OnKioskAppCacheUpdated(const std::string& app_id) {}
+
  protected:
   virtual ~KioskAppManagerObserver() {}
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_APP_MODE_KIOSK_APP_MANAGER_OBSERVER_H_