Here’s an interesting new feature to expect in Android P: you’ll be able to use your smartphone as a Bluetooth keyboard or mouse for other devices. Weird? Yes, very. But we’re intrigued either way.
This new feature has been hinted at by a few code commits, which seems like it’s how we’re finding out about all of Android P’s new features. There is quite a bit of code pointing at a new Bluetooth profile (HID, or human interface device) being added an enabled to Android devices running Android P, which will make them act like any other regular input device.
There have previously been a few apps that require root access that enabled this functionality on other Bluetooth devices, but going forward it will be a more standardized experience; less fiddling while being more widely adopted and function out of the box. A device will need to be running the latest version of Android, obviously, but being able to emulate a trackpad can be really nifty for things like Razer’s Project Linda. Being able to pair up with a smart TV or streaming box sounds pretty useful, too.
source: XDA Developers