[gnome-flashback] input-sources: add support for shift_caps_switch

[Alberts Muktupāvels <muktupavels src gnome org>]

commit e066f319dff67ae27263057e7a1e75a26c0c6cb6
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Dec 1 00:54:45 2019 +0200

    input-sources: add support for shift_caps_switch
    
    https://gitlab.gnome.org/GNOME/gnome-flashback/issues/24

 .../libinput-sources/gf-input-source-manager.c         | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
---
diff --git a/gnome-flashback/libinput-sources/gf-input-source-manager.c 
b/gnome-flashback/libinput-sources/gf-input-source-manager.c
index 39bb0ea..35e3477 100644
--- a/gnome-flashback/libinput-sources/gf-input-source-manager.c
+++ b/gnome-flashback/libinput-sources/gf-input-source-manager.c
@@ -551,6 +551,24 @@ modifiers_accelerator_activated_cb (GfKeybindings    *keybindings,
 
       gf_input_source_activate (next_source, TRUE);
     }
+  else if (keybinding_type == GF_KEYBINDING_ISO_FIRST_GROUP)
+    {
+      GfInputSource *first_source;
+
+      first_source = g_hash_table_lookup (manager->input_sources,
+                                          GUINT_TO_POINTER (0));
+
+      gf_input_source_activate (first_source, TRUE);
+    }
+  else if (keybinding_type == GF_KEYBINDING_ISO_LAST_GROUP)
+    {
+      GfInputSource *last_source;
+
+      last_source = g_hash_table_lookup (manager->input_sources,
+                                         g_list_nth_data (keys, size - 1));
+
+      gf_input_source_activate (last_source, TRUE);
+    }
 
   g_list_free (keys);