Allow child classes to override the overlay location for the
update image.

b/10952479

Change-Id: I59bb834f271f702fb529054dab7926b816fa35cc
diff --git a/screen_ui.h b/screen_ui.h
index 0bd220f..fc35d95 100644
--- a/screen_ui.h
+++ b/screen_ui.h
@@ -58,6 +58,9 @@
     enum UIElement { HEADER, MENU, MENU_SEL_BG, MENU_SEL_FG, LOG, TEXT_FILL };
     virtual void SetColor(UIElement e);
 
+  protected:
+    int install_overlay_offset_x, install_overlay_offset_y;
+
   private:
     Icon currentIcon;
     int installingFrame;
@@ -99,7 +102,6 @@
     int animation_fps;
     int indeterminate_frames;
     int installing_frames;
-    int install_overlay_offset_x, install_overlay_offset_y;
     int overlay_offset_x, overlay_offset_y;
 
     void draw_install_overlay_locked(int frame);