[cros,de-hack] Get rid of singleton for the WebUILoginScreen.

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

Index: chrome/browser/ui/webui/chromeos/login/oobe_ui.h
diff --git a/chrome/browser/ui/webui/chromeos/login/oobe_ui.h b/chrome/browser/ui/webui/chromeos/login/oobe_ui.h
index ff9dfa55318d776e2599f2c25db0aa0de0aa01c0..0ab57054d9574553234318804ed03c6d35f0cf5d 100644
--- a/chrome/browser/ui/webui/chromeos/login/oobe_ui.h
+++ b/chrome/browser/ui/webui/chromeos/login/oobe_ui.h
@@ -17,6 +17,7 @@ namespace chromeos {
 class BaseScreenHandler;
 class CoreOobeHandler;
 class SigninScreenHandler;
+class SigninScreenHandlerDelegate;
 }
 
 namespace chromeos {
@@ -52,7 +53,7 @@ class OobeUI : public OobeDisplay,
   void ShowOobeUI(bool show);
 
   // Shows the signin screen.
-  void ShowSigninScreen();
+  void ShowSigninScreen(SigninScreenHandlerDelegate* delegate);
 
   // Called when the login main frame has been rendered.
   void OnLoginPromptVisible();