benchmark: add benchmark for WHATWG URL properties

PR-URL: https://github.com/nodejs/node/pull/10408
Fixes: https://github.com/nodejs/node/issues/10376
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/url/whatwg-url-properties.js

@@ -0,0 +1,91 @@
+'use strict';
+
+var common = require('../common.js');
+var URL = require('url').URL;
+
+var bench = common.createBenchmark(main, {
+  url: [
+    'http://example.com/',
+    'https://encrypted.google.com/search?q=url&q=site:npmjs.org&hl=en',
+    'javascript:alert("node is awesome");',
+    'http://user:pass@foo.bar.com:21/aaa/zzz?l=24#test'
+  ],
+  prop: ['toString', 'href', 'origin', 'protocol',
+    'username', 'password', 'host', 'hostname', 'port',
+    'pathname', 'search', 'searchParams', 'hash'],
+  n: [1e4]
+});
+
+function setAndGet(n, url, prop, alternative) {
+  const old = url[prop];
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    url[prop] = n % 2 === 0 ? alternative : old;  // set
+    url[prop];  // get
+  }
+  bench.end(n);
+}
+
+function get(n, url, prop) {
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    url[prop];  // get
+  }
+  bench.end(n);
+}
+
+function stringify(n, url, prop) {
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    url.toString();
+  }
+  bench.end(n);
+}
+
+const alternatives = {
+  href: 'http://user:pass@foo.bar.com:21/aaa/zzz?l=25#test',
+  protocol: 'https:',
+  username: 'user2',
+  password: 'pass2',
+  host: 'foo.bar.net:22',
+  hostname: 'foo.bar.org',
+  port: '23',
+  pathname: '/aaa/bbb',
+  search: '?k=99',
+  hash: '#abcd'
+};
+
+function getAlternative(prop) {
+  return alternatives[prop];
+}
+
+function main(conf) {
+  const n = conf.n | 0;
+  const url = new URL(conf.url);
+  const prop = conf.prop;
+
+  switch (prop) {
+    case 'protocol':
+    case 'username':
+    case 'password':
+    case 'host':
+    case 'hostname':
+    case 'port':
+    case 'pathname':
+    case 'search':
+    case 'hash':
+      setAndGet(n, url, prop, getAlternative(prop));
+      break;
+    // TODO: move href to the first group when the setter lands.
+    case 'href':
+    case 'origin':
+    case 'searchParams':
+      get(n, url, prop);
+      break;
+    case 'toString':
+      stringify(n, url);
+      break;
+    default:
+      throw new Error('Unknown prop');
+  }
+}