Add Track button to My Orders table.

<?php
/*
Plugin Name: Tracking button to My Orders
Plugin URI: https://www.damiencarbery.com/
Description: Add a Track button to the My Orders page. Use the CMB2 tracking info from <a href="https://www.damiencarbery.com/2020/01/add-tracking-info-to-woocommerce-order/">https://www.damiencarbery.com/2020/01/add-tracking-info-to-woocommerce-order/</a>.
Author: Damien Carbery
Author URI: https://www.damiencarbery.com
Version: 0.1
*/


// Add Track button only when the tracking plugin is active.
add_action( 'plugins_loaded', 'dcwd_check_for_tracking_plugin' );
function dcwd_check_for_tracking_plugin() {
    if ( function_exists( 'dcwd_add_tracking_info_to_order_completed_email' ) ) {
        add_filter( 'woocommerce_my_account_my_orders_actions', 'dcwd_add_track_button_to_my_orders_actions', 20, 2 );
    }
}


// Verify that the order has a tracking url before displaying the Track button.
function dcwd_add_track_button_to_my_orders_actions( $actions, $order ) {
    $tracking_url = get_post_meta( $order->get_id(), 'tracking_url', true );
    if ( !empty( $tracking_url ) ) {
        $actions[ 'track' ] = array( 'url'  => $tracking_url, 'name' => 'Track' );
    }

    return $actions;
}