Implement 'URLSearchParams'

third_party/WebKit/LayoutTests/fast/domurl/resources/urlsearchparams-worker.js

+importScripts("../../../resources/testharness.js")
+
+test(function() {
+    assert_true('URLSearchParams' in self);
+    assert_true('toString' in URLSearchParams.prototype);
+    assert_true('append' in URLSearchParams.prototype);
+    assert_true('delete' in URLSearchParams.prototype);
+    assert_true('get' in URLSearchParams.prototype);
+    assert_true('getAll' in URLSearchParams.prototype);
+    assert_true('has' in URLSearchParams.prototype);
+    assert_true('set' in URLSearchParams.prototype);
+}, 'URLSearchParams interface');
+
+done();