MAGETWO-55301: Enable tax rate calculation on address change without shipping methods

Author: pdohogne-magento

app/code/Magento/Checkout/view/frontend/web/js/model/cart/estimate-service.js

@@ -19,7 +19,7 @@ define([
     quote.shippingAddress.subscribe(function () {
         var type = quote.shippingAddress().getType();
 
-        if (quote.isVirtual() || window.checkoutConfig.activeCarriers.length() === 0) {
+        if (quote.isVirtual() || (window.checkoutConfig && window.checkoutConfig.activeCarriers.length() === 0)) {
             // update totals block when estimated address was set
             totalsProcessors['default'] = totalsDefaultProvider;
             totalsProcessors[type] ?