Google introduced a new API called Bubbles which would make it easier for app developers to push more visible notifications directly on top of the users display, much like how Facebook Messenger does with its Chat Heads feature.
The folks over at XDA-Developers were able to manually enable the Android Message Bubbles and theyve posted some screen shots of the feature in action. Theres honestly not much new to the feature compared to Facebooks Chat Heads as you receive a message, youll get a visual notification on top of your screen, so you dont have to leave the app youre using.
You can drag and place the floating bubble to other parts of the screen, or you can drag it to the bottom to dismiss it again, much like Chat Heads. As someone who dislikes Facebooks Messengers Chat Heads (frankly, I find it annoying and obtrusive), Im glad there will still be an option to disable the feature.