[dconf-editor] Create NotificationsRevealer on the fly.

[Arnaud B. <arnaudb src gnome org>]

commit b5b482cbf832d214938f005a212a8c3006b2b55d
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Dec 14 10:55:38 2018 +0100

    Create NotificationsRevealer on the fly.

 editor/browser-window.ui   |  7 +------
 editor/browser-window.vala | 22 ++++++++++++++++++++--
 2 files changed, 21 insertions(+), 8 deletions(-)
---
diff --git a/editor/browser-window.ui b/editor/browser-window.ui
index 5a8f81b..89ce242 100644
--- a/editor/browser-window.ui
+++ b/editor/browser-window.ui
@@ -9,7 +9,7 @@
     <signal name="button-press-event" handler="on_button_press_event"/>
     <signal name="destroy" handler="on_destroy"/>
     <child>
-      <object class="GtkOverlay">
+      <object class="GtkOverlay" id="main_overlay">
         <property name="visible">True</property>
         <child>
           <object class="GtkGrid" id="main_grid">
@@ -17,11 +17,6 @@
             <property name="orientation">vertical</property>
           </object>
         </child>
-        <child type="overlay">
-          <object class="NotificationsRevealer" id="notifications_revealer">
-            <property name="visible">True</property>
-          </object>
-        </child>
       </object>
     </child>
   </template>
diff --git a/editor/browser-window.vala b/editor/browser-window.vala
index ec9b67c..d2dc625 100644
--- a/editor/browser-window.vala
+++ b/editor/browser-window.vala
@@ -49,7 +49,6 @@ private abstract class BrowserWindow : AdaptativeWindow, AdaptativeWidget
 
         add_adaptative_child (headerbar);
         add_adaptative_child (browser_view);
-        add_adaptative_child (notifications_revealer);
         add_adaptative_child (this);
     }
 
@@ -902,15 +901,34 @@ private abstract class BrowserWindow : AdaptativeWindow, AdaptativeWidget
     * * notifications
     \*/
 
-    [GtkChild] private NotificationsRevealer notifications_revealer;
+    [GtkChild] private Overlay main_overlay;
+
+    private bool notifications_revealer_created = false;
+    private NotificationsRevealer notifications_revealer;
+
+    private void create_notifications_revealer ()
+    {
+        notifications_revealer = new NotificationsRevealer ();
+        add_adaptative_child (notifications_revealer);
+        notifications_revealer.set_window_size (window_size);
+        notifications_revealer.show ();
+        main_overlay.add_overlay (notifications_revealer);
+        notifications_revealer_created = true;
+    }
 
     protected void show_notification (string notification)
     {
+        if (!notifications_revealer_created)
+            create_notifications_revealer ();
+
         notifications_revealer.show_notification (notification);
     }
 
     protected void hide_notification ()
     {
+        if (!notifications_revealer_created)
+            return;
+
         notifications_revealer.hide_notification ();
     }
 }