Version 52.0.2743.0 dev (64-bit)
Platform 8350.2.0 (Official Build) dev-channel link
Firmware Google_Link.2695.1.169

What steps will reproduce the problem?
(1) Go to https://googlechrome.github.io/samples/web-bluetooth/gap-characteristics.html
(2) Click "Get Bluetooth Device's GAP Characteristics" button
(3) Click "Get help" link in Bluetooth chooser
(4) New tab is opened, go back to previous tab

What is the expected output?
Live output should show some generic "NotFoundError" error

What do you see instead?
Live output still displays "Requesting Bluetooth Device..."

I think navigator.bluetooth.requestDevice should settle when user clicks "Get Help" because there's no way to communicate to the developer that it needs to reset its UI otherwise. 
OR Bluetooth chooser could still be opened when coming back to the previous tab but... I'm not sure that would work well in all scenarii.

For info, on Android the promise is rejected with "NotFoundError: User cancelled the requestDevice() chooser."