The avatar menu button has just been redesigned in the last chromium build for Mac.
As you've probably noticed¹, this change is part of the much wider effort called the new Profile Management that the chromium team has been working on. My two favorite parts about this feature are definitely: - the multiple accounts tied to a unique Chrome Profile. - the ability to lock a profile and unlock it from the User Manager.
To give it a try, you can enable the experimental chrome://flags/#enable-new-profile-management flag in Chrome Canary and restart.
Last Chrome OS Dev Update has eventually made easy for everyone to enable the Kiosk Mode¹. We can now add Chrome Kiosk Apps from the Web Store and launch them from the main sign-in screen² as you can see below.
As you know, the Kiosk Mode is most suited for any single app use case such as in guest registration desks or library catalog stations. In this mode, the single kiosk app will load full-screen.
Here's how you can play with this mode. Go to chrome://extensions, click on the new "Manage kiosk applications..." button, paste a Kiosk App Webstore URL³, click on the "Add" button and you're "Done". For information, a Kiosk App⁴ is a Chrome App with the "kiosk_enabled" key set to "true" in its manifest and obviously designed for this mode in mind such as Hangouts⁵ as we saw.
Warning! Be careful with the "Permanently keep this device in kiosk mode" checkbox which does exactly what is says. If you just want to simply play with the Kiosk App, don't check it.
Finally, log out and go back to the main sign-in screen where you'll see next to your user pod another pod for the Chrome Kiosk App you've just installed. This is still work in progress but I'm convinced this move will definitely help developers to fully test their Kiosk Apps.