In short: Chrome OS project managers have approved the complete removal of at least one notification related to the Android Runtime for Chrome (ARC), based on a recent change spotted in the Chromium Gerrit. The rework is presently marked as "active" and hasn't gone into effect yet and there's no indication as to whether users would need to wait for a full OS update before it does. Once the change is implemented, it will eliminate a notification that currently pops up when a user moves from a Chrome OS firmware build that doesn't support Android apps to one that supports the applications.
Background: The reason for the removal, as noted in the commit itself, is that the notification never seems to have worked as intended to begin with. Instead of only showing up immediately following an update-associated system restart, it appears to have been showing up at random. Since it is actually intended to inform users that they can install and run Android applications following an OS update but doesn't, the notification is essentially useless. Moreover, all new Chrome OS devices and most that haven't reached their 'end of life' already support the apps, with the integration between Android and Chrome getting closer all the time. So it really doesn't serve much of a purpose regardless.
Impact: The implication of this single change to Chrome OS's underlying notifications system isn't necessarily going to make a huge difference and probably should have happened quite some time ago. Removing it will mostly just reduce the size of the overall Chrome OS code – albeit by a negligible degree – and should at least prevent annoyance for some users who may have been seeing it appear at random intervals. Having said that, minute changes can and do add up over time. More directly, incremental tweaks to the system and code clean-ups will ultimately make Chrome OS a faster operating system with fewer quirks and a more premium feel. That's particularly true anywhere resources are incorrectly being allocated for unnecessary processes. What's more, fixes such as this one can tie up loose ends associated with 'listener' actions and events which could eventually become security concerns in their own right if left unchecked.