[PATCH 3/6] ole32, propsys: Rework PROPVARIANT (de)serialization

[Vincent Povirk]

>       * The only interface to property (de)serialization provided by
>         ole32.dll, the StgConvertVariantToProperty()/
>         StgConvertPropertyToVariant() functions, are poorly documented,
>         hard to implement (HRESULTs need to be converted to NTSTATUS
>         exceptions) and even more unpleasant to use (because one would
>         need to catch the NTSTATUS exception and convert it back to a
>         HRESULT). This is rather crazy and cumbersome.

I remember being concerned that StgConvertPropertyToVariant does not
accept a size for the serialized value. This is not good when we don't
trust the data we're reading.

So, at least for deserialization I don't think we should use the public API.