[gnome-calendar] calendar-management-page: Add helper to retrieve titlebar

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 804479ebcc5e3ba2123e90e6c943ab84da83bb1a
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Jun 3 22:59:38 2019 -0300

    calendar-management-page: Add helper to retrieve titlebar

 src/gui/calendar-management/gcal-calendar-management-page.c | 11 +++++++++++
 src/gui/calendar-management/gcal-calendar-management-page.h |  2 ++
 2 files changed, 13 insertions(+)
---
diff --git a/src/gui/calendar-management/gcal-calendar-management-page.c 
b/src/gui/calendar-management/gcal-calendar-management-page.c
index 344d014c..b3ae1ca6 100644
--- a/src/gui/calendar-management/gcal-calendar-management-page.c
+++ b/src/gui/calendar-management/gcal-calendar-management-page.c
@@ -106,3 +106,14 @@ gcal_calendar_management_page_switch_page (GcalCalendarManagementPage *self,
 
   g_signal_emit (self, signals[SWITCH_PAGE], 0, page_name, page_data);
 }
+
+GtkHeaderBar*
+gcal_calendar_management_page_get_titlebar (GcalCalendarManagementPage *self)
+{
+  GtkWidget *toplevel;
+
+  toplevel = gtk_widget_get_toplevel (GTK_WIDGET (self));
+  g_assert (toplevel != NULL);
+
+  return GTK_HEADER_BAR (gtk_window_get_titlebar (GTK_WINDOW (toplevel)));
+}
diff --git a/src/gui/calendar-management/gcal-calendar-management-page.h 
b/src/gui/calendar-management/gcal-calendar-management-page.h
index de2edeec..04835823 100644
--- a/src/gui/calendar-management/gcal-calendar-management-page.h
+++ b/src/gui/calendar-management/gcal-calendar-management-page.h
@@ -59,4 +59,6 @@ void                 gcal_calendar_management_page_switch_page   (GcalCalendarMa
                                                                   const gchar                *page_name,
                                                                   gpointer                    page_data);
 
+GtkHeaderBar*        gcal_calendar_management_page_get_titlebar  (GcalCalendarManagementPage *self);
+
 G_END_DECLS