Add Chromium-only Blender WebEngine parity work

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

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+/* SPDX-FileCopyrightText: 2026 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#pragma once
+
+CCL_NAMESPACE_BEGIN
+
+using ImplicitSharingInfo = const void *;
+
+using ImplicitSharingUserAddFn = void (*)(ImplicitSharingInfo);
+using ImplicitSharingUserRemoveFn = void (*)(ImplicitSharingInfo);
+
+extern ImplicitSharingUserAddFn g_implicit_sharing_user_add_fn;
+extern ImplicitSharingUserRemoveFn g_implicit_sharing_user_remove_fn;
+
+/**
+ * Set function pointers to be called when implicit sharing (use count tracking) is enabled.
+ * "Sharing info" references that own data like attribute arrays are passed as void pointers to
+ * various Cycles API functions, and these functions are called to change the reference count.
+ */
+void implicit_sharing_init(ImplicitSharingUserAddFn add_fn, ImplicitSharingUserRemoveFn remove_fn);
+
+CCL_NAMESPACE_END