Implement 'URLSearchParams'

third_party/WebKit/Source/core/dom/URLSearchParams.idl

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://url.spec.whatwg.org/#interface-urlsearchparams
+
+[
+    Constructor(optional (USVString or URLSearchParams) init = ""),
+    GarbageCollected,
+    Exposed=(Window,Worker)
+] interface URLSearchParams {
+    void append(USVString name, USVString value);
+    [ImplementedAs=deleteAllWithName] void delete(USVString name);
+    USVString? get(USVString name);
+    sequence<USVString> getAll(USVString name);
+    boolean has(USVString name);
+    void set(USVString name, USVString value);
+    
+    iterable<USVString, USVString>;
+    stringifier;
+};