mash: improves browser frame decorations

ash/public/cpp/window_style.h

Index: ash/public/cpp/window_style.h
diff --git a/ash/public/cpp/window_style.h b/ash/public/cpp/window_style.h
new file mode 100644
index 0000000000000000000000000000000000000000..804ca488d77fecde8d0df61acfd0e40131e98e93
--- /dev/null
+++ b/ash/public/cpp/window_style.h
@@ -0,0 +1,19 @@
+// Copyright 2017 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.
+
+#ifndef ASH_PUBLIC_CPP_WINDOW_STYLE_H_
+#define ASH_PUBLIC_CPP_WINDOW_STYLE_H_
+
+#include <stdint.h>
+
+#include "ash/public/cpp/ash_public_export.h"
+
+namespace ash {
+
+// Returns true if |type| is a valid WindowStyle.
+ASH_PUBLIC_EXPORT bool IsValidWindowStyle(int32_t style);
+
+}  // namespace ash
+
+#endif  // ASH_PUBLIC_CPP_WINDOW_STYLE_H_