app-info: Make use of the XdpAppInfo subclasses

Implement existing functions using the new private fields of XdpAppInfo
and the new vfuncs of the class. Also instantiate the subclasses.

This allows us to remove the app info kind and the kind specific fields
from XdpAppInfo and delegates all of that to the subclasses.

src/background.c

@@ -812,9 +812,9 @@ handle_request_background_in_thread_func (GTask *task,
       guint32 response = 2;
       g_autoptr(GVariant) results = NULL;
       g_autoptr(GError) error = NULL;
-      g_autoptr(GAppInfo) info = NULL;
+      GAppInfo *info = NULL;
 
-      info = xdp_app_info_load_app_info (request->app_info);
+      info = xdp_app_info_get_gappinfo (request->app_info);
       app_id = info ? xdp_get_app_id_from_desktop_id (g_app_info_get_id (info)) : g_strdup (id);
 
       title = g_strdup_printf (_("Allow %s to run in the background?"), info ? g_app_info_get_display_name (info) : id);

src/location.c

@@ -532,11 +532,9 @@ handle_start_in_thread_func (GTask *task,
 
       if (g_strcmp0 (id, "") != 0)
         {
-          g_autoptr(GAppInfo) info = NULL;
+          GAppInfo *info = xdp_app_info_get_gappinfo (request->app_info);
           const gchar *name = NULL;
 
-          info = xdp_app_info_load_app_info (request->app_info);
-
           if (info)
             {
               name = g_app_info_get_display_name (G_APP_INFO (info));

src/wallpaper.c

@@ -186,11 +186,9 @@ handle_set_wallpaper_in_thread_func (GTask *task,
 
       if (g_strcmp0 (id, "") != 0)
         {
-          g_autoptr(GAppInfo) info = NULL;
+          GAppInfo *info = xdp_app_info_get_gappinfo (request->app_info);
           const gchar *name = NULL;
 
-          info = xdp_app_info_load_app_info (request->app_info);
-
           if (info)
             {
               name = g_app_info_get_display_name (G_APP_INFO (info));