Nope, both DVD & Blu-ray. From Building Windows 8, Making Windows Media Center available in Windows 8:
Also related:
If VLC can ship a free DVD player, why can't Microsoft? | ZDNet
Maximum PC | VLC Offers a Free DVD Player, Why Can’t Microsoft?
It would seem to me that for OEM's to ship PCs that support native DVD playback, the cost will be higher because they will not have as much bargaining power to license the codecs.
What worries me is not that having Windows Media Player will be a cost add-on or that it may cost more for OEMs to obtain licenses for codecs. I don't want to return to 2006 and the need to warn users about downloading codecs, no longer being able to explain that under normal circumstances all needed codecs are built into Windows (one example from 2006: VideosCodec and More on Fake Codecs).