[gtk] popover: Fix an oversight in gap coord computation

[Timm Bäder <baedert src gnome org>]

commit 616a83fb53d009dc9dd92e67f7678ac0ddb088a1
Author: Timm Bäder <mail baedert org>
Date:   Mon Jan 27 13:01:37 2020 +0100

    popover: Fix an oversight in gap coord computation
    
    This caused a border to show up between the popover arrow and the
    contents.

 gtk/gtkpopover.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 24e154e8a9..5a75e1156c 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -798,7 +798,7 @@ gtk_popover_get_gap_coords (GtkPopover *popover,
 
   pos = priv->final_position;
 
-  style = gtk_css_node_get_style (gtk_widget_get_css_node (widget));
+  style = gtk_css_node_get_style (gtk_widget_get_css_node (priv->contents_widget));
   border_radius = _gtk_css_number_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_TOP_LEFT_RADIUS), 100);
   border_top = _gtk_css_number_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_TOP_WIDTH), 100);
   border_right = _gtk_css_number_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_RIGHT_WIDTH), 100);