[geary: 1/2] main-window: replace GtkApplicationWindow with HdyApplicaitonWindow

[Michael Gratton <mjog src gnome org>]

commit dc6fb34422baa975b19631d238cf9784f4bbbbfb
Author: Julian Sparber <julian sparber net>
Date:   Thu Oct 8 16:59:43 2020 +0200

    main-window: replace GtkApplicationWindow with HdyApplicaitonWindow
    
    HdyApplicationWindow moves the titlebar into the content area of the
    window which allows us to split the current main-titlebar and move the
    parts directly into the leaflets without the need of swipe groups nor
    size groups.

 src/client/application/application-main-window.vala | 7 ++-----
 ui/application-main-window.ui                       | 5 +----
 2 files changed, 3 insertions(+), 9 deletions(-)
---
diff --git a/src/client/application/application-main-window.vala 
b/src/client/application/application-main-window.vala
index 8af06365b..b6f785a0c 100644
--- a/src/client/application/application-main-window.vala
+++ b/src/client/application/application-main-window.vala
@@ -8,7 +8,7 @@
 
 [GtkTemplate (ui = "/org/gnome/Geary/application-main-window.ui")]
 public class Application.MainWindow :
-    Gtk.ApplicationWindow, Geary.BaseInterface {
+    Hdy.ApplicationWindow, Geary.BaseInterface {
 
 
     // Named actions.
@@ -1322,10 +1322,7 @@ public class Application.MainWindow :
             this.main_toolbar.show_close_button = false;
             this.main_layout.pack_start(main_toolbar, false, true, 0);
         } else {
-            var titlebar = new Hdy.TitleBar();
-            titlebar.show();
-            titlebar.add(this.main_toolbar);
-            set_titlebar(titlebar);
+            this.main_layout.pack_start(main_toolbar, false, true, 0);
         }
 
         this.main_toolbar.add_conversation_actions(this.conversation_actions);
diff --git a/ui/application-main-window.ui b/ui/application-main-window.ui
index ffef59300..d54d365af 100644
--- a/ui/application-main-window.ui
+++ b/ui/application-main-window.ui
@@ -2,7 +2,7 @@
 <!-- Generated with glade 3.22.2 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
-  <template class="ApplicationMainWindow" parent="GtkApplicationWindow">
+  <template class="ApplicationMainWindow" parent="HdyApplicationWindow">
     <property name="events">GDK_KEY_PRESS_MASK | GDK_KEY_RELEASE_MASK | GDK_FOCUS_CHANGE_MASK | 
GDK_STRUCTURE_MASK</property>
     <property name="show_menubar">False</property>
     <signal name="delete-event" handler="on_delete_event" swapped="no"/>
@@ -10,9 +10,6 @@
     <signal name="focus-out-event" handler="on_focus_event" swapped="no"/>
     <signal name="map" handler="on_map" swapped="no"/>
     <signal name="unmap" handler="on_unmap" swapped="no"/>
-    <child type="titlebar">
-      <placeholder/>
-    </child>
     <child>
       <object class="GtkOverlay" id="overlay">
         <property name="visible">True</property>