url: adding WHATWG URL support

Implements WHATWG URL support. Example:

```
var u = new url.URL('http://example.org');
```

Many, many other commits improving the implementation have been squashed
into this backport PR. They are not listed separately here for brevity.

Backport-PR-URL: #17365
PR-URL: #7448
Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

benchmark/url/legacy-vs-whatwg-url-get-prop.js

@@ -0,0 +1,97 @@
+'use strict';
+const common = require('../common.js');
+const url = require('url');
+const URL = url.URL;
+const assert = require('assert');
+const inputs = require('../fixtures/url-inputs.js').urls;
+
+const bench = common.createBenchmark(main, {
+  type: Object.keys(inputs),
+  method: ['legacy', 'whatwg'],
+  n: [1e5]
+});
+
+// At the time of writing, when using a passed property name to index
+// the object, Crankshaft would generate a LoadKeyedGeneric even when it
+// remains a constant in the function, so here we must use the literal
+// instead to get a LoadNamedField.
+function useLegacy(n, input) {
+  const obj = url.parse(input);
+  const noDead = {
+    protocol: obj.protocol,
+    auth: obj.auth,
+    host: obj.host,
+    hostname: obj.hostname,
+    port: obj.port,
+    pathname: obj.pathname,
+    search: obj.search,
+    hash: obj.hash
+  };
+  // It's necessary to assign the values to an object
+  // to avoid loop invariant code motion.
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead.protocol = obj.protocol;
+    noDead.auth = obj.auth;
+    noDead.host = obj.host;
+    noDead.hostname = obj.hostname;
+    noDead.port = obj.port;
+    noDead.pathname = obj.pathname;
+    noDead.search = obj.search;
+    noDead.hash = obj.hash;
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function useWHATWG(n, input) {
+  const obj = new URL(input);
+  const noDead = {
+    protocol: obj.protocol,
+    auth: `${obj.username}:${obj.password}`,
+    host: obj.host,
+    hostname: obj.hostname,
+    port: obj.port,
+    pathname: obj.pathname,
+    search: obj.search,
+    hash: obj.hash
+  };
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead.protocol = obj.protocol;
+    noDead.auth = `${obj.username}:${obj.password}`;
+    noDead.host = obj.host;
+    noDead.hostname = obj.hostname;
+    noDead.port = obj.port;
+    noDead.pathname = obj.pathname;
+    noDead.search = obj.search;
+    noDead.hash = obj.hash;
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function main(conf) {
+  const type = conf.type;
+  const n = conf.n | 0;
+  const method = conf.method;
+
+  const input = inputs[type];
+  if (!input) {
+    throw new Error('Unknown input type');
+  }
+
+  var noDead;  // Avoid dead code elimination.
+  switch (method) {
+    case 'legacy':
+      noDead = useLegacy(n, input);
+      break;
+    case 'whatwg':
+      noDead = useWHATWG(n, input);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+
+  assert.ok(noDead);
+}

benchmark/url/legacy-vs-whatwg-url-parse.js

@@ -0,0 +1,57 @@
+'use strict';
+const common = require('../common.js');
+const url = require('url');
+const URL = url.URL;
+const assert = require('assert');
+const inputs = require('../fixtures/url-inputs.js').urls;
+
+const bench = common.createBenchmark(main, {
+  type: Object.keys(inputs),
+  method: ['legacy', 'whatwg'],
+  n: [1e5]
+});
+
+function useLegacy(n, input) {
+  var noDead = url.parse(input);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead = url.parse(input);
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function useWHATWG(n, input) {
+  var noDead = new URL(input);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead = new URL(input);
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function main(conf) {
+  const type = conf.type;
+  const n = conf.n | 0;
+  const method = conf.method;
+
+  const input = inputs[type];
+  if (!input) {
+    throw new Error('Unknown input type');
+  }
+
+  var noDead;  // Avoid dead code elimination.
+  switch (method) {
+    case 'legacy':
+      noDead = useLegacy(n, input);
+      break;
+    case 'whatwg':
+      noDead = useWHATWG(n, input);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+
+  assert.ok(noDead);
+}

benchmark/url/legacy-vs-whatwg-url-searchparams-parse.js

@@ -0,0 +1,51 @@
+'use strict';
+const common = require('../common.js');
+const { URLSearchParams } = require('url');
+const querystring = require('querystring');
+const inputs = require('../fixtures/url-inputs.js').searchParams;
+
+const bench = common.createBenchmark(main, {
+  type: Object.keys(inputs),
+  method: ['legacy', 'whatwg'],
+  n: [1e6]
+});
+
+function useLegacy(n, input) {
+  querystring.parse(input);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    querystring.parse(input);
+  }
+  bench.end(n);
+}
+
+function useWHATWG(n, input) {
+  new URLSearchParams(input);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    new URLSearchParams(input);
+  }
+  bench.end(n);
+}
+
+function main(conf) {
+  const type = conf.type;
+  const n = conf.n | 0;
+  const method = conf.method;
+
+  const input = inputs[type];
+  if (!input) {
+    throw new Error('Unknown input type');
+  }
+
+  switch (method) {
+    case 'legacy':
+      useLegacy(n, input);
+      break;
+    case 'whatwg':
+      useWHATWG(n, input);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+}

benchmark/url/legacy-vs-whatwg-url-searchparams-serialize.js

@@ -0,0 +1,53 @@
+'use strict';
+const common = require('../common.js');
+const { URLSearchParams } = require('url');
+const querystring = require('querystring');
+const inputs = require('../fixtures/url-inputs.js').searchParams;
+
+const bench = common.createBenchmark(main, {
+  type: Object.keys(inputs),
+  method: ['legacy', 'whatwg'],
+  n: [1e6]
+});
+
+function useLegacy(n, input, prop) {
+  const obj = querystring.parse(input);
+  querystring.stringify(obj);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    querystring.stringify(obj);
+  }
+  bench.end(n);
+}
+
+function useWHATWG(n, input, prop) {
+  const obj = new URLSearchParams(input);
+  obj.toString();
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    obj.toString();
+  }
+  bench.end(n);
+}
+
+function main(conf) {
+  const type = conf.type;
+  const n = conf.n | 0;
+  const method = conf.method;
+
+  const input = inputs[type];
+  if (!input) {
+    throw new Error('Unknown input type');
+  }
+
+  switch (method) {
+    case 'legacy':
+      useLegacy(n, input);
+      break;
+    case 'whatwg':
+      useWHATWG(n, input);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+}

benchmark/url/legacy-vs-whatwg-url-serialize.js

@@ -0,0 +1,59 @@
+'use strict';
+const common = require('../common.js');
+const url = require('url');
+const URL = url.URL;
+const assert = require('assert');
+const inputs = require('../fixtures/url-inputs.js').urls;
+
+const bench = common.createBenchmark(main, {
+  type: Object.keys(inputs),
+  method: ['legacy', 'whatwg'],
+  n: [1e5]
+});
+
+function useLegacy(n, input, prop) {
+  const obj = url.parse(input);
+  var noDead = url.format(obj);
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead = url.format(obj);
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function useWHATWG(n, input, prop) {
+  const obj = new URL(input);
+  var noDead = obj.toString();
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    noDead = obj.toString();
+  }
+  bench.end(n);
+  return noDead;
+}
+
+function main(conf) {
+  const type = conf.type;
+  const n = conf.n | 0;
+  const method = conf.method;
+
+  const input = inputs[type];
+  if (!input) {
+    throw new Error('Unknown input type');
+  }
+
+  var noDead;  // Avoid dead code elimination.
+  switch (method) {
+    case 'legacy':
+      noDead = useLegacy(n, input);
+      break;
+    case 'whatwg':
+      noDead = useWHATWG(n, input);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+
+  assert.ok(noDead);
+}

benchmark/url/url-searchparams-iteration.js

@@ -0,0 +1,61 @@
+'use strict';
+const common = require('../common.js');
+const assert = require('assert');
+const { URLSearchParams } = require('url');
+
+const bench = common.createBenchmark(main, {
+  method: ['forEach', 'iterator'],
+  n: [1e6]
+});
+
+const str = 'one=single&two=first&three=first&two=2nd&three=2nd&three=3rd';
+
+function forEach(n) {
+  const params = new URLSearchParams(str);
+  const noDead = [];
+  const cb = (val, key) => {
+    noDead[0] = key;
+    noDead[1] = val;
+  };
+
+  bench.start();
+  for (var i = 0; i < n; i += 1)
+    params.forEach(cb);
+  bench.end(n);
+
+  assert.strictEqual(noDead[0], 'three');
+  assert.strictEqual(noDead[1], '3rd');
+}
+
+function iterator(n) {
+  const params = new URLSearchParams(str);
+  const noDead = [];
+
+  bench.start();
+  for (var i = 0; i < n; i += 1) {
+    for (const pair of params) {
+      noDead[0] = pair[0];
+      noDead[1] = pair[1];
+    }
+  }
+  bench.end(n);
+
+  assert.strictEqual(noDead[0], 'three');
+  assert.strictEqual(noDead[1], '3rd');
+}
+
+function main(conf) {
+  const method = conf.method;
+  const n = conf.n | 0;
+
+  switch (method) {
+    case 'forEach':
+      forEach(n);
+      break;
+    case 'iterator':
+      iterator(n);
+      break;
+    default:
+      throw new Error('Unknown method');
+  }
+}