That's just the Chrome Signal app playing catchup - not Chromium's fault. It's not the best app in the world. Really can't wait for the next iteration that isn't in Chrome form.
Evidently all Chrome apps are being phased out for Windows/Linux/Mac, so I can only assume they will. Not that Signal is a very feature-filled app or concept (it doesn't need to be), but it could definitely stand to be a bit more polished.
I am contemplating extracting the bits of chromium required to just make it an app container, so I can continue to run Chrome apps on the desktop. Since Chrome apps will still exist for Chromebooks it should keep working.
Electron misses some core native application type features because they are not available to it. I can't see them coming to HTML5 either. It is just a colossal stuff up all round.
Seems to me that devs would only be smart (read: not in our favor or best interest) to go where the people are; what's the ChromeOS userbase compared to that of other OSes?
Pocket, Kindle Cloud Reader, Duolingo, and Floating for YouTube are also gone.