[gtk/wip/exalm/checks] checkbutton: Sync the indicator state with the widget

[Alexander Mikhaylenko <alexm src gnome org>]

commit bad01edd2c625910c25cac563c903f7f5f31bb39
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Thu May 20 12:16:32 2021 +0500

    checkbutton: Sync the indicator state with the widget
    
    Clicking the whole check button toggles it, so make sure the hover and
    active states are propagated to the indicator like in GTK3.

 gtk/gtkcheckbutton.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/gtk/gtkcheckbutton.c b/gtk/gtkcheckbutton.c
index e9a30a1ce3..87df3e5844 100644
--- a/gtk/gtkcheckbutton.c
+++ b/gtk/gtkcheckbutton.c
@@ -399,6 +399,19 @@ get_group_active_button (GtkCheckButton *self)
   return NULL;
 }
 
+static void
+gtk_check_button_state_flags_changed (GtkWidget     *widget,
+                                      GtkStateFlags  previous_flags)
+{
+  GtkCheckButton *self = GTK_CHECK_BUTTON (widget);
+  GtkCheckButtonPrivate *priv = gtk_check_button_get_instance_private (self);
+  GtkStateFlags state = gtk_widget_get_state_flags (GTK_WIDGET (self));
+
+  gtk_widget_set_state_flags (priv->indicator_widget, state, TRUE);
+
+  GTK_WIDGET_CLASS (gtk_check_button_parent_class)->state_flags_changed (widget, previous_flags);
+}
+
 static gboolean
 gtk_check_button_focus (GtkWidget         *widget,
                         GtkDirectionType   direction)
@@ -499,6 +512,7 @@ gtk_check_button_class_init (GtkCheckButtonClass *class)
   object_class->set_property = gtk_check_button_set_property;
   object_class->get_property = gtk_check_button_get_property;
 
+  widget_class->state_flags_changed = gtk_check_button_state_flags_changed;
   widget_class->focus = gtk_check_button_focus;
 
   class->activate = gtk_check_button_real_activate;