UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

Steps to reproduce the problem:
1. with a simple web MIDI app open, connect a midi device  
2. physically disconnect the device from the system
3. refresh the browser

What is the expected behavior?
a statechange event should be emitted to acknowledge that the device has been disconnected.

What went wrong?
In this case the statechange doesn't seem to get emitted and refreshing the browser in this state causes the browser to become unresponsive.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 59.0.3071.86  Channel: stable
OS Version: 10
Flash Version: 

This doesn't seem to be an issue in Canary nor on build 56 of Chrome