UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36

Steps to reproduce the problem:
This is currently an unsupported feature

What is the expected behavior?
With the new APK approach to "Add to home screen" applications, there's an opportunity to have parity with native applications with regards to background geolocation in service workers, possibly using the web budget api. The permission model of PWA's with APKs is such that many of the privacy concerns around background geolocation for the web in general can be mitigated with "Add to home screen" PWAs and an expanded json manifest with a user prompt.

What went wrong?
For any application requiring background geolocation, such as fleet and asset management, field workers, disaster relief, etc... it is currently impossible to implement as a PWA. An expansion of permissions (via an addition to the json manifest and a user prompt when installing) for background geolocation would bring PWAs closer to parity with native apps.

Did this work before? N/A 

Does this work in other browsers? No
 No browser is currently supporting this feature

Chrome version: 61.0.3163.100  Channel: stable
OS Version: 10.0
Flash Version: