[PATCH v9 0/5] MR8703: combase: Implement HSTRING marshaling functions.

[Vibhav Pant (＠vibhavp)]

Add tests + implementations for the `HSTRING_User{Size, Marshal, Unmarshal, Free}` methods, required by proxies generated for interfaces that utilize HSTRING.

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  v9: combase: Implement HSTRING_User{Unmarshal, Free}.

https://gitlab.winehq.org/wine/wine/-/merge_requests/8703