[resend PATCH 4/4] gdiplus/metafile: Implement EmfPlusRecordTypeSetClipRegion playback

[Vincent Povirk]

> +            return GdipSetClipRegion(real_metafile->playback_graphics, real_metafile->objtable[region].u.region,
> +                (flags >> 8) & 0xf);

This clip region needs to be intersected with the clip region from
when the metafile began playing, similar to what we do for world
transforms.

Alternately, we could try to repurpose our existing code for handling
gdi32 clipping and transforms.

It just occurred to me that applications could tell the difference
between those approaches, so we should probably have tests.