In Ubuntu 17.10 Google Chrome indicator icons are missing. In the previous versions of Ubuntu, Google Chrome was adding a main icon form where it was possible to completely terminate its processes, plus the Extension icons (eg. Hangouts icon):
After the update to 17.10 some indicator icons are shown (eg. Steam, InSync and Dropbox) but the one from Chrome are missing:
You won't find another solution than adding the extension Topicon Plus.
GNOME got rid of its notification panel in 3.26. Ubuntu added an extension to manage that. But it's not as feature complete as Topicon Plus.
Either use TopIcons Plus or Unite extension. Both works in Ubuntu 17.10.
Fixed in Chrome 66.0.3359.33.
Old answer
I found a temporary workaround: forcing XDG_CURRENT_DESKTOP=Unity for Chrome.
In Ubuntu 17.10 XDG_CURRENT_DESKTOP has changed to ubuntu:GNOME and this seems to not be correctly handled by Chromium/Chrome (bug report here).
Starting Chromium/Chrome with XDG_CURRENT_DESKTOP=Unity seems to temporarily fix the issue.
To make it permanent I just modified my Chrome launcher to always start it with that value:
env XDG_CURRENT_DESKTOP=Unity /usr/bin/google-chrome-beta %U
