Show `theme_type_variation`s in the inspector on `Control`s that inherit a theme

`theme_type_variation`s are now shown in the children and children of children
that inherit a theme from a parent `Control` node.

scene/gui/control.cpp

@@ -461,9 +461,30 @@ void Control::_validate_property(PropertyInfo &p_property) const {
 	if (p_property.name == "theme_type_variation") {
 		List<StringName> names;
 
-		// Only the default theme and the project theme are used for the list of options.
-		// This is an imposed limitation to simplify the logic needed to leverage those options.
 		ThemeDB::get_singleton()->get_default_theme()->get_type_variation_list(get_class_name(), &names);
+
+		// Iterate to find all themes.
+		Control *tmp_control = Object::cast_to<Control>(get_parent());
+		Window *tmp_window = Object::cast_to<Window>(get_parent());
+		while (tmp_control || tmp_window) {
+			// We go up and any non Control/Window will break the chain.
+			if (tmp_control) {
+				if (tmp_control->get_theme().is_valid()) {
+					tmp_control->get_theme()->get_type_variation_list(get_class_name(), &names);
+				}
+				tmp_window = Object::cast_to<Window>(tmp_control->get_parent());
+				tmp_control = Object::cast_to<Control>(tmp_control->get_parent());
+			} else { // Window.
+				if (tmp_window->get_theme().is_valid()) {
+					tmp_window->get_theme()->get_type_variation_list(get_class_name(), &names);
+				}
+				tmp_control = Object::cast_to<Control>(tmp_window->get_parent());
+				tmp_window = Object::cast_to<Window>(tmp_window->get_parent());
+			}
+		}
+		if (get_theme().is_valid()) {
+			get_theme()->get_type_variation_list(get_class_name(), &names);
+		}
 		if (ThemeDB::get_singleton()->get_project_theme().is_valid()) {
 			ThemeDB::get_singleton()->get_project_theme()->get_type_variation_list(get_class_name(), &names);
 		}

scene/main/window.cpp

@@ -247,9 +247,30 @@ void Window::_validate_property(PropertyInfo &p_property) const {
 	} else if (p_property.name == "theme_type_variation") {
 		List<StringName> names;
 
-		// Only the default theme and the project theme are used for the list of options.
-		// This is an imposed limitation to simplify the logic needed to leverage those options.
 		ThemeDB::get_singleton()->get_default_theme()->get_type_variation_list(get_class_name(), &names);
+
+		// Iterate to find all themes.
+		Control *tmp_control = Object::cast_to<Control>(get_parent());
+		Window *tmp_window = Object::cast_to<Window>(get_parent());
+		while (tmp_control || tmp_window) {
+			// We go up and any non Control/Window will break the chain.
+			if (tmp_control) {
+				if (tmp_control->get_theme().is_valid()) {
+					tmp_control->get_theme()->get_type_variation_list(get_class_name(), &names);
+				}
+				tmp_window = Object::cast_to<Window>(tmp_control->get_parent());
+				tmp_control = Object::cast_to<Control>(tmp_control->get_parent());
+			} else { // Window.
+				if (tmp_window->get_theme().is_valid()) {
+					tmp_window->get_theme()->get_type_variation_list(get_class_name(), &names);
+				}
+				tmp_control = Object::cast_to<Control>(tmp_window->get_parent());
+				tmp_window = Object::cast_to<Window>(tmp_window->get_parent());
+			}
+		}
+		if (get_theme().is_valid()) {
+			get_theme()->get_type_variation_list(get_class_name(), &names);
+		}
 		if (ThemeDB::get_singleton()->get_project_theme().is_valid()) {
 			ThemeDB::get_singleton()->get_project_theme()->get_type_variation_list(get_class_name(), &names);
 		}