source: branches/4.6/src/wp-admin/includes/class-theme-upgrader-skin.php

<?php
/**
 * Upgrader API: Theme_Upgrader_Skin class
 *
 * @package WordPress
 * @subpackage Upgrader
 * @since 4.6.0
 */

/**
 * Theme Upgrader Skin for WordPress Theme Upgrades.
 *
 * @since 2.8.0
 * @since 4.6.0 Moved to its own file from wp-admin/includes/class-wp-upgrader-skins.php.
 *
 * @see WP_Upgrader_Skin
 */
class Theme_Upgrader_Skin extends WP_Upgrader_Skin {
        public $theme = '';

        /**
         *
         * @param array $args
         */
        public function __construct($args = array()) {
                $defaults = array( 'url' => '', 'theme' => '', 'nonce' => '', 'title' => __('Update Theme') );
                $args = wp_parse_args($args, $defaults);

                $this->theme = $args['theme'];

                parent::__construct($args);
        }

        /**
         * @access public
         */
        public function after() {
                $this->decrement_update_count( 'theme' );

                $update_actions = array();
                if ( ! empty( $this->upgrader->result['destination_name'] ) && $theme_info = $this->upgrader->theme_info() ) {
                        $name       = $theme_info->display('Name');
                        $stylesheet = $this->upgrader->result['destination_name'];
                        $template   = $theme_info->get_template();

                        $activate_link = add_query_arg( array(
                                'action'     => 'activate',
                                'template'   => urlencode( $template ),
                                'stylesheet' => urlencode( $stylesheet ),
                        ), admin_url('themes.php') );
                        $activate_link = wp_nonce_url( $activate_link, 'switch-theme_' . $stylesheet );

                        if ( get_stylesheet() == $stylesheet ) {
                                if ( current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
                                        $update_actions['preview']  = '<a href="' . wp_customize_url( $stylesheet ) . '" class="hide-if-no-customize load-customize"><span aria-hidden="true">' . __( 'Customize' ) . '</span><span class="screen-reader-text">' . sprintf( __( 'Customize &#8220;%s&#8221;' ), $name ) . '</span></a>';
                                }
                        } elseif ( current_user_can( 'switch_themes' ) ) {
                                if ( current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
                                        $update_actions['preview'] = '<a href="' . wp_customize_url( $stylesheet ) . '" class="hide-if-no-customize load-customize"><span aria-hidden="true">' . __( 'Live Preview' ) . '</span><span class="screen-reader-text">' . sprintf( __( 'Live Preview &#8220;%s&#8221;' ), $name ) . '</span></a>';
                                }
                                $update_actions['activate'] = '<a href="' . esc_url( $activate_link ) . '" class="activatelink"><span aria-hidden="true">' . __( 'Activate' ) . '</span><span class="screen-reader-text">' . sprintf( __( 'Activate &#8220;%s&#8221;' ), $name ) . '</span></a>';
                        }

                        if ( ! $this->result || is_wp_error( $this->result ) || is_network_admin() )
                                unset( $update_actions['preview'], $update_actions['activate'] );
                }

                $update_actions['themes_page'] = '<a href="' . self_admin_url( 'themes.php' ) . '" target="_parent">' . __( 'Return to Themes page' ) . '</a>';

                /**
                 * Filters the list of action links available following a single theme update.
                 *
                 * @since 2.8.0
                 *
                 * @param array  $update_actions Array of theme action links.
                 * @param string $theme          Theme directory name.
                 */
                $update_actions = apply_filters( 'update_theme_complete_actions', $update_actions, $this->theme );

                if ( ! empty($update_actions) )
                        $this->feedback(implode(' | ', (array)$update_actions));
        }
}