[shotwell] Switch slideshow dialog to use headerbar

[Jens Georg <jensgeorg src gnome org>]

commit ff52d0f048149fc3b44812a1e922174e26614175
Author: Jens Georg <mail jensge org>
Date:   Wed May 23 23:33:06 2018 +0200

    Switch slideshow dialog to use headerbar

 src/SlideshowPage.vala   |    2 ++
 ui/slideshow_settings.ui |    9 ++++++++-
 2 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/src/SlideshowPage.vala b/src/SlideshowPage.vala
index 62cd3fe..18fef7f 100644
--- a/src/SlideshowPage.vala
+++ b/src/SlideshowPage.vala
@@ -41,6 +41,8 @@ class SlideshowPage : SinglePhotoPage {
         Gtk.CheckButton show_title_button;
         
         public SettingsDialog() {
+            Object (use_header_bar: Resources.use_header_bar());
+
             double delay = Config.Facade.get_instance().get_slideshow_delay();
 
             set_transient_for(AppWindow.get_fullscreen());
diff --git a/ui/slideshow_settings.ui b/ui/slideshow_settings.ui
index 5400793..fed66a3 100644
--- a/ui/slideshow_settings.ui
+++ b/ui/slideshow_settings.ui
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- Generated with glade 3.20.0 -->
+<!-- Generated with glade 3.22.1 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
   <object class="GtkAdjustment" id="delay_adjustment">
@@ -21,6 +21,9 @@
     <property name="title" translatable="yes">Settings</property>
     <property name="modal">True</property>
     <property name="type_hint">dialog</property>
+    <child>
+      <placeholder/>
+    </child>
     <child internal-child="vbox">
       <object class="GtkBox">
         <property name="can_focus">False</property>
@@ -50,8 +53,12 @@
                 <property name="visible">True</property>
                 <property name="can_focus">True</property>
                 <property name="can_default">True</property>
+                <property name="has_default">True</property>
                 <property name="receives_default">True</property>
                 <property name="use_underline">True</property>
+                <style>
+                  <class name="default-action"/>
+                </style>
               </object>
               <packing>
                 <property name="expand">True</property>