[gtk/switch-icons: 3/4] Fix gtk4-icon-browser

[Matthias Clasen <matthiasc src gnome org>]

commit 603fc1c54ca7da8c0e1e97d65795f5d641725e67
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jan 24 16:11:45 2019 -0500

    Fix gtk4-icon-browser
    
    It was broken by a recent GtkDialog change that renamed
    the internal vbox child to content_area.

 demos/icon-browser/window.ui | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/demos/icon-browser/window.ui b/demos/icon-browser/window.ui
index d060f97c38..1bbe6a3402 100644
--- a/demos/icon-browser/window.ui
+++ b/demos/icon-browser/window.ui
@@ -121,7 +121,7 @@
     <property name="use-header-bar">1</property>
     <property name="resizable">0</property>
     <property name="hide-on-close">1</property>
-    <child internal-child="vbox">
+    <child internal-child="content_area">
       <object class="GtkBox">
         <child>
           <object class="GtkGrid">