Chrome Version : 66.0.3359.117
OS version     : 10.13.3 (17D102)

What steps will reproduce the problem?
(1) Launch Chrome and open a good number of tabs and windows
(2) Make sure to include sites that do display notifications like Calendar, Hangouts, etc.
(3) Put the Mac to sleep (close the lid).
(4) Awake it and try to use Chrome or any other application.

What is the expected result?
Everything should work normally.

What happens instead?
The whole system gets to a crawl because somehow Chrome can do that. It's hard to even kill Chrome but once that's done the system immediately gets back to normal.
If I have Activity Monitor already launched (it's impossible to launch it when this happens) it shows what I think is the browser process using >100% CPU.
Another characteristic of this issue is that every and all notifications that should have been shown in the potentially many hours the laptop was sleeping -- event notifications, IM messages, emails, etc --, are now shown one right after the other.
This can take many minutes to recover. It's always much quicker to kill Chrome (if ever possible), relaunch and restore tabs.