Chrome Version       : 50.0.2661.91 cros x86_64 7978.66.3
OS Version: Chrome
URLs (if applicable) : facebook.com

User received the update to M50 and was browsing facebook shortly after.

The machine froze. Mouse would not move. Keyboard would not respond. We waited about 1 minute but it did not recover.

I tapped the power key to see if it would respond and the machine immediately rebooted.

I filed a feedback report after it restarted. Haven't been able to repro. No recent ID in chrome://crashes

https://feedback.corp.google.com/product/208/neutron?lReport=8641728835