How to close all tabs/windows of a specific chrome user/profile?

This is not possible right now, but you can star this feature request if you'd like to see it introduced: https://code.google.com/p/chromium/issues/detail?id=130656

It seems that a new features was introduced in chrome's stable build - mine is 55.0.2883.75 (64-bit). See screencap below.

It's a new option in the profile's left click: Close all your windows.

The problem is that it doesn't always restore all the closed windows and sometimes doesn't even restore at all, even though my startup setting is set to Continue where you left off.

EDIT: It seems that there are issues with the restoration and cleanup. More info here.

edit(2017-08-09) - No need for right click anymore. Left click does the job.

This has been possible for a while. Here's a screenshot from Chromium 71:

There are some bugs still, e.g. some windows may not be restored, or some extensions may keep running. But if you have one window per profile, its tabs are saved and restored fine.