As of version 184.108.40.2063.g7ff4a0dc with the windowing changes that were made the class name was left the default "Chrome_WidgetWin_0". I assume this was an oversight by the programming team as in the past the class name was "SpotifyMainWindow".
While on the surface this seems like no big deal the issue is that many programs rely on this to tell if Spotify is locally running or not, among other reasons, for use with the official API. Is this something that will be changed/reverted in a future update?
We know it's not ideal, but we can confirm this was an intentional change. If this causes any issues, we'd recommend heading over to our developer support page to discuss possible work arounds.