Accept options in history APIs to allow scroll restoration to be disabled

Source/core/frame/StateOptions.idl

Index: Source/core/frame/StateOptions.idl
diff --git a/Source/core/frame/StateOptions.idl b/Source/core/frame/StateOptions.idl
new file mode 100644
index 0000000000000000000000000000000000000000..cb9315b5e6807dd66cb68fd04c9ee8bcad13f153
--- /dev/null
+++ b/Source/core/frame/StateOptions.idl
@@ -0,0 +1,11 @@
+// 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.
+
+// Spec work is being tracked on W3C bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=28553
+
+enum ScrollRestoration {"auto", "manual"};
+
+dictionary StateOptions {
+    ScrollRestoration scrollRestoration = "auto";
+};