cros: Disable system tray help/lock buttons during supervised user creation

ash/system/tiles/tiles_default_view.h

Index: ash/system/tiles/tiles_default_view.h
diff --git a/ash/system/tiles/tiles_default_view.h b/ash/system/tiles/tiles_default_view.h
index 075e7aae0c53387c4d63445c745edb25c25a2c2b..d6fe3a8a87ec29136696a4a41470a13ead35f021 100644
--- a/ash/system/tiles/tiles_default_view.h
+++ b/ash/system/tiles/tiles_default_view.h
@@ -6,7 +6,6 @@
 #define ASH_SYSTEM_TILES_TILES_DEFAULT_VIEW_H_
 
 #include "ash/ash_export.h"
-#include "ash/login_status.h"
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
@@ -23,7 +22,7 @@ class SystemTrayItem;
 class ASH_EXPORT TilesDefaultView : public views::View,
                                     public views::ButtonListener {
  public:
-  TilesDefaultView(SystemTrayItem* owner, LoginStatus login);
+  explicit TilesDefaultView(SystemTrayItem* owner);
   ~TilesDefaultView() override;
 
   // Sets the layout manager and child views of |this|.
@@ -43,7 +42,6 @@ class ASH_EXPORT TilesDefaultView : public views::View,
   friend class TrayTilesTest;
 
   SystemTrayItem* owner_;
-  LoginStatus login_;
 
   // Pointers to the child buttons of |this|. Note that some buttons may not
   // exist (depending on the user's current login status, for instance), in