Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/util/concurrent_set.h

@@ -0,0 +1,19 @@
+/* SPDX-FileCopyrightText: 2011-2025 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#pragma once
+
+/* TBB includes <windows.h>, do it ourselves first so we are sure
+ * WIN32_LEAN_AND_MEAN and similar are defined beforehand. */
+#ifdef _WIN32
+#  include "util/windows.h"
+#endif
+
+#include <tbb/concurrent_set.h>
+
+CCL_NAMESPACE_BEGIN
+
+using tbb::concurrent_set;
+
+CCL_NAMESPACE_END