Not on Shield currently, but Chromecast Ultra -- yes on DV.
Edit -- referring to playback.
I just confirmed I'm getting Dolby Vision in Canada too. Tested with Joker on Chromecast Ultra.
I wonder if Google have finally embraced 4K HDR10 / DV - HEVC video encoding for such Google Play Movies ?
HEVC encoding is what is needed if the 2019 Nvidia Shield has any hope of Play Movies - 4K DV video playback.
I confirm the Dolby Vision logo appears in both movies at the Play Store website in my country as well, now it's Dolby Atmos' turn.