cros: Replace WizardController string constants with OobeScreen values.

chrome/browser/chromeos/login/session/user_session_manager.h

Index: chrome/browser/chromeos/login/session/user_session_manager.h
diff --git a/chrome/browser/chromeos/login/session/user_session_manager.h b/chrome/browser/chromeos/login/session/user_session_manager.h
index 9fd6ab2598fc4061dbc956fd468813b9fbc08d6c..f1b4f176a6d59ea6706eb535553795c887a99d15 100644
--- a/chrome/browser/chromeos/login/session/user_session_manager.h
+++ b/chrome/browser/chromeos/login/session/user_session_manager.h
@@ -16,6 +16,7 @@
 #include "chrome/browser/chromeos/base/locale_util.h"
 #include "chrome/browser/chromeos/eol_notification.h"
 #include "chrome/browser/chromeos/hats/hats_notification_controller.h"
+#include "chrome/browser/chromeos/login/oobe_screen.h"
 #include "chrome/browser/chromeos/login/quick_unlock/quick_unlock_notification_controller.h"
 #include "chrome/browser/chromeos/login/signin/oauth2_login_manager.h"
 #include "chrome/browser/chromeos/login/signin/token_handle_util.h"
@@ -316,7 +317,7 @@ class UserSessionManager
   void FinalizePrepareProfile(Profile* profile);
 
   // Starts out-of-box flow with the specified screen.
-  void ActivateWizard(const std::string& screen_name);
+  void ActivateWizard(OobeScreen screen);
 
   // Adds first-time login URLs.
   void InitializeStartUrls() const;