Occasionally, some VR tests are failing due to hitting an assert related to the Choreographer. This is similar to  Issue 740161 , but happens randomly instead of 100% of the time. Sample failure:

C  132.083s Main  ********************************************************************************
C  132.083s Main  Detailed Logs
C  132.083s Main  ********************************************************************************
C  132.083s Main  [FAIL] org.chromium.chrome.browser.vr_shell.WebVrInputTest#testPresentationLocksFocus:
C  132.083s Main  java.lang.AssertionError
C  132.083s Main  	at org.chromium.chrome.browser.vr_shell.VrShellDelegate$VSyncEstimator$1.doFrame(VrShellDelegate.java:520)
C  132.083s Main  	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:765)
C  132.083s Main  	at android.view.Choreographer.doCallbacks(Choreographer.java:580)
C  132.083s Main  	at android.view.Choreographer.doFrame(Choreographer.java:549)
C  132.083s Main  	at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
C  132.083s Main  	at android.os.Handler.handleCallback(Handler.java:739)
C  132.083s Main  	at android.os.Handler.dispatchMessage(Handler.java:95)
C  132.083s Main  	at android.os.Looper.loop(Looper.java:135)
C  132.083s Main  	at android.app.ActivityThread.main(ActivityThread.java:5254)
C  132.083s Main  	at java.lang.reflect.Method.invoke(Native Method)
C  132.083s Main  	at java.lang.reflect.Method.invoke(Method.java:372)
C  132.083s Main  	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
C  132.083s Main  	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

This seems to only happen on Nexus 5's with L.