Reorder the NativeViews attached to a view via kViewHostKey according to the position of the view

ui/views/widget/native_widget_private.h

Index: ui/views/widget/native_widget_private.h
diff --git a/ui/views/widget/native_widget_private.h b/ui/views/widget/native_widget_private.h
index 9d43c789b1a3759d0e507307956f038cd87d68ae..fac085e9c99c3719103365b78ee7de50018eb1ed 100644
--- a/ui/views/widget/native_widget_private.h
+++ b/ui/views/widget/native_widget_private.h
@@ -64,6 +64,10 @@ class VIEWS_EXPORT NativeWidgetPrivate : public NativeWidget {
   static void ReparentNativeView(gfx::NativeView native_view,
                                  gfx::NativeView new_parent);
 
+  // Reorder the child layers of |parent| so that their order matches the order
+  // the order of views with layers / views with attached layers in |root_view|.
+  static void ReorderLayers(gfx::NativeView parent, View* root_view);
+
   // Returns true if any mouse button is currently down.
   static bool IsMouseButtonDown();