Add device policy to disallow shutdown - ash UI modifications

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
index 5f97fbb0d11fcae4f742d63eba445e07fbc5e125..73d7d398300aa329f602cc44bb2bcf64f8c2cd8f 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
@@ -245,6 +245,11 @@ class SigninScreenHandler
   // Required Local State preferences.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
+  // Checks whether the device policy allows the system to be shut down and if
+  // so initiates the shutdown. If system shutdown is forbidden this function
+  // triggers a reboot.
+  static void RequestShutdown();
+
   // OobeUI::Observer implemetation.
   virtual void OnCurrentScreenChanged(OobeUI::Screen current_screen,
                                       OobeUI::Screen new_screen) override;
@@ -353,6 +358,7 @@ class SigninScreenHandler
                                  const std::string& locale,
                                  const std::string& input_method);
   void HandleOfflineLogin(const base::ListValue* args);
+  void HandleRestartSystem();
   void HandleShutdownSystem();
   void HandleLoadWallpaper(const std::string& email);
   void HandleRebootSystem();