Before we get started, this flag is currently available in the Canary channel of Chrome OS. It will most likely land in one of the upcoming Dev channel releases.
A few weeks ago, I shared a code change note from the Chromium repository which talked about adding “notification indicators” to Chrome OS. This feature is now available on Chrome OS canary channel behind a flag.
Name: Notification Indicators
Description: Enable notification indicators, which appear on app icons when a notification is active. This will also enable notifications in context menus. – Chrome OS
Direct link: chrome://flags/#enable-notification-indicator
I tested this feature briefly using the Hangouts app, and it did work:
I also noticed a notification counter on the system tray, which I think is new. I do not remember seeing the number of pending notifications showing up there. Feel free to correct if I am wrong.
Update: Looks like the notification counter is not new.
It might take a few more weeks for this feature to start rolling out to Beta and Stable channels. Stay tuned for updates.