Add DialogShowParams to <dialog>'s show() and showModal()

third_party/WebKit/Source/core/html/DialogShowParams.idl

Index: third_party/WebKit/Source/core/html/DialogShowParams.idl
diff --git a/third_party/WebKit/Source/core/html/DialogShowParams.idl b/third_party/WebKit/Source/core/html/DialogShowParams.idl
new file mode 100644
index 0000000000000000000000000000000000000000..4eee73ac6e180a7f3def1f369191d31e9b1f1a52
--- /dev/null
+++ b/third_party/WebKit/Source/core/html/DialogShowParams.idl
@@ -0,0 +1,7 @@
+// Copyright 2016 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.
+
+dictionary DialogShowParams {
+    boolean skipInitialFocus = false;
+};