Stack trace:
java.lang.RuntimeException: An error occurred while executing doInBackground()
  at android.os.AsyncTask$3.done(AsyncTask.java:325)
  at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
  at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
  at java.util.concurrent.FutureTask.run(FutureTask.java:242)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
  at java.lang.Thread.run(Thread.java:761)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
  at android.os.Handler.<init>(Handler.java:200)
  at android.os.Handler.<init>(Handler.java:114)
  at org.chromium.chrome.browser.vr_shell.VrShellDelegate.isVrCoreCompatible(VrShellDelegate.java:1106)
  at org.chromium.chrome.browser.vr_shell.VrShellDelegate.getVrSupportLevel(VrShellDelegate.java:282)
  at org.chromium.chrome.browser.vr_shell.VrShellDelegate$1.doInBackground(VrShellDelegate.java:310)
  at org.chromium.chrome.browser.vr_shell.VrShellDelegate$1.doInBackground(VrShellDelegate.java:302)
  at android.os.AsyncTask$2.call(AsyncTask.java:305)
  at java.util.concurrent.FutureTask.run(FutureTask.java:237)
  ... 3 more

VrShellDelegate.isVrCoreCompatible() is called on a background thread from an AsyncTask, so a) posting a task asynchronously to the same thread isn't allowed, and b) it would be the wrong thread to show UI anyway.