Theme_Upgrader::check_parent_theme_filter( bool $install_result, array $hook_extra, array $child_result )

	public function check_parent_theme_filter( $install_result, $hook_extra, $child_result ) {
		// Check to see if we need to install a parent theme
		$theme_info = $this->theme_info();

		if ( ! $theme_info->parent() )
			return $install_result;

		$this->skin->feedback( 'parent_theme_search' );

		if ( ! $theme_info->parent()->errors() ) {
			$this->skin->feedback( 'parent_theme_currently_installed', $theme_info->parent()->display('Name'), $theme_info->parent()->display('Version') );
			// We already have the theme, fall through.
			return $install_result;
		}

		// We don't have the parent theme, let's install it.
		$api = themes_api('theme_information', array('slug' => $theme_info->get('Template'), 'fields' => array('sections' => false, 'tags' => false) ) ); //Save on a bit of bandwidth.

		if ( ! $api || is_wp_error($api) ) {
			$this->skin->feedback( 'parent_theme_not_found', $theme_info->get('Template') );
			// Don't show activate or preview actions after installation
			add_filter('install_theme_complete_actions', array($this, 'hide_activate_preview_actions') );
			return $install_result;
		}

		// Backup required data we're going to override:
		$child_api = $this->skin->api;
		$child_success_message = $this->strings['process_success'];

		// Override them
		$this->skin->api = $api;
		$this->strings['process_success_specific'] = $this->strings['parent_theme_install_success'];//, $api->name, $api->version);

		$this->skin->feedback('parent_theme_prepare_install', $api->name, $api->version);

		add_filter('install_theme_complete_actions', '__return_false', 999); // Don't show any actions after installing the theme.

		// Install the parent theme
		$parent_result = $this->run( array(
			'package' => $api->download_link,
			'destination' => get_theme_root(),
			'clear_destination' => false, //Do not overwrite files.
			'clear_working' => true
		) );

		if ( is_wp_error($parent_result) )
			add_filter('install_theme_complete_actions', array($this, 'hide_activate_preview_actions') );

		// Start cleaning up after the parents installation
		remove_filter('install_theme_complete_actions', '__return_false', 999);

		// Reset child's result and data
		$this->result = $child_result;
		$this->skin->api = $child_api;
		$this->strings['process_success'] = $child_success_message;

		return $install_result;
	}