Add URLSearchParams.prototype.sort()

tests/url_tests.js

@@ -151,6 +151,15 @@ QUnit.test('Parameter Mutation', function(assert) {
   url.searchParams.set('b', '3');
   assert.deepEqual(url.searchParams.getAll('b'), ['3']);
   assert.equal(url.href, 'http://example.com/?a=1&b=3&c=1');
+
+  url.href = 'http://example.com?c=1&a=2&a=4&b=3';
+  url.searchParams.sort();
+  assert.equal(url.search, '?a=2&a=4&b=3&c=1');
+
+  // Preserving the relative order
+  url.href = 'http://example.com?c=1&a=4&a=2&b=3';
+  url.searchParams.sort();
+  assert.equal(url.search, '?a=4&a=2&b=3&c=1');
 });
 
 QUnit.test('Parameter Encoding', function(assert) {

url.js

@@ -240,6 +240,14 @@
         }, writable: true, enumerable: true, configurable: true
       },
 
+      sort: {
+        value: function () {
+          this._list.sort(function(pair1, pair2) {
+            return pair1.name.localeCompare(pair2.name);
+          });
+        }, writable: true, enumerable: true, configurable: true
+      },
+
       toString: {
         value: function () {
           return urlencoded_serialize(this._list);