textarea_safe

function themename_servicebox_vc(){

    vc_map(array(
        "name" => esc_html__("Service Box", "text_domain"),
        "base" => "service_text",
        "category" => "Content",
        "params" => array(
            array(
                'type' => 'textarea_safe',
                'heading' => esc_html__( 'Map embed iframe', 'js_composer' ),
                'param_name' => 'link',
                'value' => '<iframe src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d6304.829986131271!2d-122.4746968033092!3d37.80374752160443!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x808586e6302615a1%3A0x86bd130251757c00!2sStorey+Ave%2C+San+Francisco%2C+CA+94129!5e0!3m2!1sen!2sus!4v1435826432051" width="600" height="450" frameborder="0" style="border:0" allowfullscreen></iframe>',
                'description' => sprintf( esc_html__( 'Visit %s to create your map (Step by step: 1) Find location 2) Click the cog symbol in the lower right corner and select "Share or embed map" 3) On modal window select "Embed map" 4) Copy iframe code and paste it).' ), '<a href="https://www.google.com/maps" target="_blank">' . esc_html__( 'Google maps', 'js_composer' ) . '</a>' ),
            ),
        )
    ));

add_action('vc_before_init', 'themename_servicebox_vc');