Using WooCommerce Product Search and replacing the default Search Form in Storefront and its child themes

woocommerce-product-search-storefront.php

<?php
function storefront_product_search() {
    if ( function_exists('storefront_is_woocommerce_activated' ) ) {
        if ( storefront_is_woocommerce_activated() ) { ?>
            <div class="site-search">
            <?php
            if ( function_exists( 'woocommerce_product_search' ) ) {
                echo woocommerce_product_search();
            } else {
                the_widget( 'WC_Widget_Product_Search', 'title=' );
            }
            ?>
            </div>
            <?php
        }
    }
}