We've featured something similar but the Smart Lock for Chrome is an official one from Google. This special unlocking feature works on a Chromebook with just an Android phone or tablet nearby. Simply sign in to unlock Chromebook without having to click anything on the keyboard or entering a passcode. All you need to do is access your Android phone.
This seems to be a nice and useful feature but not all Android phones can unlock your Chromebook. Smartphone must run at least Android 5.0 Lollipop and must have Bluetooth connectivity. Meanwhile, Chromebook must be installed with Chrome OS 40+ or above and of course, Bluetooth for the remote unlocking to work. Tablets are not yet supported but Google could be working on it.
Since this feature works over Bluetooth, the Android phone's Bluetooth must always be turned on and phone must be within a 100-foot Bluetooth range and near the Chromebook. Smart Lock for Chrome must first be set up on both the Android phone and the Chromebook. You can allow multiple phones to unlock Chromebook but you should turn off the connections not in use.
If you have more than one compatible phone nearby, turn off the ones you won’t be using. To sign in to Chromebook, make sure phone and computer are both connected to the Internet, click account picture found in the bottom right corner. Click Settings > Show advanced settings. Click “set up” on the Smart Lock section. Follow instructions to pair phone and Chromebook. Make sure phone and Chromebook can detect each other’s Bluetooth connection.
SOURCE: Google Chrome