Add more browser tests for Kiosk update from usb stick.

chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h

Index: chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h b/chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h
index 069c4fe4c4708efe53bdd6ebcdd6db9cba264251..ac93e12f925f7df5170096ee1ba1088aa24a21da 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_manager_observer.h
@@ -29,6 +29,10 @@ class KioskAppManagerObserver {
   // Invoked when kiosk app cache is updated for |app_id|.
   virtual void OnKioskAppCacheUpdated(const std::string& app_id) {}
 
+  // Invoked when kiosk app updating from usb stick has been completed.
+  // |success| indicates if all the updates are completed successfully.
+  virtual void OnKioskAppExternalUpdateComplete(bool success) {}
+
  protected:
   virtual ~KioskAppManagerObserver() {}
 };