url, test: including base argument in originFor

- Add tests to check if the `originFor` implementation
  for WHATWG url parsing is correnct.
- Fix `originFor` by including a base as argument

PR-URL: https://github.com/nodejs/node/pull/10021
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/url.js

@@ -781,9 +781,9 @@ Object.defineProperty(URLSearchParamsIteratorPrototype, Symbol.toStringTag, {
   configurable: true
 });
 
-URL.originFor = function(url) {
+URL.originFor = function(url, base) {
   if (!(url instanceof URL))
-    url = new URL(url);
+    url = new URL(url, base);
   var origin;
   const protocol = url.protocol;
   switch (protocol) {

test/parallel/test-whatwg-url-origin-for.js

@@ -0,0 +1,19 @@
+'use strict';
+
+const common = require('../common');
+
+const URL = require('url').URL;
+const path = require('path');
+const assert = require('assert');
+const tests = require(path.join(common.fixturesDir, 'url-tests.json'));
+
+for (const test of tests) {
+  if (typeof test === 'string')
+    continue;
+
+  if (test.origin) {
+    const origin = URL.originFor(test.input, test.base);
+    // Pass true to origin.toString() to enable unicode serialization.
+    assert.strictEqual(origin.toString(true), test.origin);
+  }
+}