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..e7415c5d85eb76454222beee7377546c4fb8d950 100644
--- a/ui/views/widget/native_widget_private.h
+++ b/ui/views/widget/native_widget_private.h
@@ -101,6 +101,15 @@ class VIEWS_EXPORT NativeWidgetPrivate : public NativeWidget {
   virtual gfx::Vector2d CalculateOffsetToAncestorWithLayer(
       ui::Layer** layer_parent) = 0;
 
+  // Reorder the child layers of the widget's layer so that their order matches
+  // the order of views with layers / views with attached layers in the view
+  // hierarchy.
+  virtual void ReorderLayers() = 0;
+
+  // Returns true if a child NativeView is attached to one of the widget's
+  // views.
+  virtual bool HasNativeViewAttachedToViewTree() const = 0;
+
   // Notifies the NativeWidget that a view was removed from the Widget's view
   // hierarchy.
   virtual void ViewRemoved(View* view) = 0;