UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10032.86.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.140 Safari/537.36
Platform: 10032.86.0 (Official Build) stable-channel cyan

Steps to reproduce the problem:
This is easily reproducible with the TestNav app (https://play.google.com/store/apps/details?id=com.pearson.testnav&hl=en) 

1. Launch the TestNav app
2. If you see the "Where do you want to go?" page, scroll down and pick reference in the lower left hand corner
3. Now you should see a sign in page with "Reference" above the Sign In. If you don't, click on the user dude in the upper right hand corner and pick "choose a different customer"
4. Log in with the the username and password g1
5. App tries to go full screen and pin the screen

What is the expected behavior?
App should be full screen and screen pinned

What went wrong?
App is crashing

Did this work before? No 

Chrome version: 63.0.3239.140  Channel: n/a
OS Version: 10032.86.0
Flash Version: 

This app works with no issues on Android 5 and up with actual Android devices.