[shotwell] Properly chain up AppWindow and siblings

[Jens Georg <jensgeorg src gnome org>]

commit 49ced8dcc02a31b25efc748761cb7061fab4e4b1
Author: Jens Georg <mail jensge org>
Date:   Fri Feb 22 11:42:17 2019 +0100

    Properly chain up AppWindow and siblings

 src/AppWindow.vala             | 2 ++
 src/direct/DirectWindow.vala   | 2 ++
 src/library/LibraryWindow.vala | 2 ++
 3 files changed, 6 insertions(+)
---
diff --git a/src/AppWindow.vala b/src/AppWindow.vala
index ad3adf74..6e0c1f79 100644
--- a/src/AppWindow.vala
+++ b/src/AppWindow.vala
@@ -406,6 +406,8 @@ public abstract class AppWindow : PageWindow {
     protected int pos_y = 0;
     
     public AppWindow() {
+        base();
+
         // although there are multiple AppWindow types, only one may exist per-process
         assert(instance == null);
         instance = this;
diff --git a/src/direct/DirectWindow.vala b/src/direct/DirectWindow.vala
index 1f33a761..9eec5b1e 100644
--- a/src/direct/DirectWindow.vala
+++ b/src/direct/DirectWindow.vala
@@ -8,6 +8,8 @@ public class DirectWindow : AppWindow {
     private DirectPhotoPage direct_photo_page;
     
     public DirectWindow(File file) {
+       base();
+
         direct_photo_page = new DirectPhotoPage(file);
         direct_photo_page.get_view().items_altered.connect(on_photo_changed);
         direct_photo_page.get_view().items_state_changed.connect(on_photo_changed);
diff --git a/src/library/LibraryWindow.vala b/src/library/LibraryWindow.vala
index 312de905..3300c6c3 100644
--- a/src/library/LibraryWindow.vala
+++ b/src/library/LibraryWindow.vala
@@ -162,6 +162,8 @@ public class LibraryWindow : AppWindow {
 #endif
     
     public LibraryWindow(ProgressMonitor progress_monitor) {
+        base();
+
         // prep sidebar and add roots
         sidebar_tree = new Sidebar.Tree(DND_TARGET_ENTRIES, Gdk.DragAction.ASK,
             external_drop_handler);