Implement URLSearchParams.

Source/core/dom/URLSearchParams.idl

+// Copyright 2014 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.
+
+// http://url.spec.whatwg.org/#interface-urlsearchparams
+
+[
+    // FIXME: use an optional union type instead,
+    // Constructor(optional (ScalarValueString or URLSearchParams) init = "");
+    // http://crbug.com/240176
+    Constructor(),
+    Constructor(URLSearchParams initial),
+    Constructor(ScalarValueString queryString),
+    GarbageCollected,
+    ImplementedAs=DOMURLSearchParams,
+] interface URLSearchParams {
+    [NotEnumerable] ScalarValueString toString();
+
+    void append(ScalarValueString name, ScalarValueString value);
+    [ImplementedAs=deleteAllWithName] void delete(ScalarValueString name);
+    [TreatReturnedNullStringAs=Null] ScalarValueString get(ScalarValueString name);
+    sequence<ScalarValueString> getAll(ScalarValueString name);
+    boolean has(ScalarValueString name);
+    void set(ScalarValueString name, ScalarValueString value);
+};