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

chrome/browser/chromeos/login/existing_user_controller.h

Index: chrome/browser/chromeos/login/existing_user_controller.h
diff --git a/chrome/browser/chromeos/login/existing_user_controller.h b/chrome/browser/chromeos/login/existing_user_controller.h
index aebf04d9264074a02bc266052ba5c13e09631184..4b514218d4ab67d9ea9f6f109e4fca19ea23c688 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.h
+++ b/chrome/browser/chromeos/login/existing_user_controller.h
@@ -85,14 +85,13 @@ class ExistingUserController : public LoginDisplay::Delegate,
     login_status_consumer_ = consumer;
   }
 
-  // Returns the LoginDisplay instance created and owned by this controller.
+  // Returns the LoginDisplay created and owned by this controller.
   // Used for testing.
   LoginDisplay* login_display() {
-    return login_display_;
+    return login_display_.get();
   }
 
   // Returns the LoginDisplayHost for this controller.
-  // Used for testing.
   LoginDisplayHost* login_display_host() {
     return host_;
   }
@@ -154,9 +153,6 @@ class ExistingUserController : public LoginDisplay::Delegate,
   // Used to execute login operations.
   scoped_ptr<LoginPerformer> login_performer_;
 
-  // Login UI implementation instance.
-  LoginDisplay* login_display_;
-
   // Delegate for login performer to be overridden by tests.
   // |this| is used if |login_performer_delegate_| is NULL.
   scoped_ptr<LoginPerformer::Delegate> login_performer_delegate_;
@@ -171,6 +167,9 @@ class ExistingUserController : public LoginDisplay::Delegate,
   // OOBE/login display host.
   LoginDisplayHost* host_;
 
+  // Login UI implementation instance.
+  scoped_ptr<LoginDisplay> login_display_;
+
   // Number of login attempts. Used to show help link when > 1 unsuccessful
   // logins for the same user.
   size_t num_login_attempts_;