clutter/backend: Initialize default font options if no schema found

When the `org.gnome.desktop.interface` schema is not found, currently
we were not initializing the font_options which means we needed to
handle that on the backend side. Instead, generate the font_options at
that moment.

As the settings are loaded the moment we assign a backend to the
settings `_clutter_settings_set_backend` which is called just after the
backend is constructed which is too early for any actor to use it for
creating a PangoContext, so the change is safe.

Also, as the font_options getter is only used in ClutterActor when
creating the PangoContext, drop the getter. As we might just store that
info somewhere else in the future.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4106>

clutter/clutter/clutter-actor.c

@@ -13001,7 +13001,6 @@ update_pango_context (ClutterBackend *backend,
 {
   ClutterSettings *settings;
   PangoFontDescription *font_desc;
-  const cairo_font_options_t *font_options;
   ClutterTextDirection dir;
   PangoDirection pango_dir;
   g_autofree char *font_name = NULL;
@@ -13018,7 +13017,6 @@ update_pango_context (ClutterBackend *backend,
   g_object_get (settings, "font-name", &font_name, NULL);
 
   /* get the configuration for the PangoContext from the backend */
-  font_options = clutter_backend_get_font_options (backend);
   resolution = clutter_backend_get_resolution (backend);
 
   font_desc = pango_font_description_from_string (font_name);
@@ -13027,7 +13025,7 @@ update_pango_context (ClutterBackend *backend,
     resolution = 96.0; /* fall back */
 
   pango_context_set_font_description (context, font_desc);
-  pango_cairo_context_set_font_options (context, font_options);
+  pango_cairo_context_set_font_options (context, backend->font_options);
   pango_cairo_context_set_resolution (context, resolution);
 
   pango_font_description_free (font_desc);

clutter/clutter/clutter-backend-private.h

@@ -105,6 +105,4 @@ void clutter_backend_destroy (ClutterBackend *backend);
 void clutter_backend_set_font_options (ClutterBackend             *backend,
                                        const cairo_font_options_t *options);
 
-const cairo_font_options_t * clutter_backend_get_font_options (ClutterBackend *backend);
-
 G_END_DECLS

clutter/clutter/clutter-backend.c

@@ -413,35 +413,6 @@ clutter_backend_set_font_options (ClutterBackend             *backend,
     }
 }
 
-/**
- * clutter_backend_get_font_options:
- * @backend: a #ClutterBackend
- *
- * Retrieves the font options for @backend.
- *
- * Return value: (transfer none): the font options of the #ClutterBackend.
- *   The returned #cairo_font_options_t is owned by the backend and should
- *   not be modified or freed
- */
-const cairo_font_options_t *
-clutter_backend_get_font_options (ClutterBackend *backend)
-{
-  g_return_val_if_fail (CLUTTER_IS_BACKEND (backend), NULL);
-
-  if (G_LIKELY (backend->font_options))
-    return backend->font_options;
-
-  backend->font_options = cairo_font_options_create ();
-
-  cairo_font_options_set_hint_style (backend->font_options, CAIRO_HINT_STYLE_NONE);
-  cairo_font_options_set_subpixel_order (backend->font_options, CAIRO_SUBPIXEL_ORDER_DEFAULT);
-  cairo_font_options_set_antialias (backend->font_options, CAIRO_ANTIALIAS_DEFAULT);
-
-  g_signal_emit (backend, backend_signals[FONT_CHANGED], 0);
-
-  return backend->font_options;
-}
-
 /**
  * clutter_backend_get_cogl_context:
  * @backend: a #ClutterBackend

clutter/clutter/clutter-settings.c

@@ -365,7 +365,18 @@ load_initial_settings (ClutterSettings *self)
   schema = g_settings_schema_source_lookup (source, font_settings_path, TRUE);
   if (!schema)
     {
+      cairo_font_options_t *font_options;
+
       g_warning ("Failed to find schema: %s", font_settings_path);
+
+      /* Fallback to the default options */
+      font_options = cairo_font_options_create ();
+      cairo_font_options_set_hint_style (font_options, CAIRO_HINT_STYLE_NONE);
+      cairo_font_options_set_subpixel_order (font_options, CAIRO_SUBPIXEL_ORDER_DEFAULT);
+      cairo_font_options_set_antialias (font_options, CAIRO_ANTIALIAS_DEFAULT);
+      clutter_backend_set_font_options (self->backend, font_options);
+
+      cairo_font_options_destroy (font_options);
     }
   else
     {