The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/09b107130f5c7a4cb377322b879ac2aac67cadbf

commit 09b107130f5c7a4cb377322b879ac2aac67cadbf
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Tue Aug 22 04:58:14 2017

VR: Add gesture token to vrdisplayactivate, remove cardboard compat hack

This CL adds a gesture token to the displayactivate event which can only
be triggered by user action (on Android, placing the phone in a VR
headset and completing controller pairing while on a WebVR site).

This CL also removes the cardboard click event used for compatibility
and supplying user gesture, as a gesture is now supplied with the
displayactivate event.

Note: Once this lands, action will be required on the part of WebVR
Origin Trial participants that were previously relying on the cardboard
compat click events to act as user gestures - they will have to
perform any gesture-requiring actions in the displayactivate handler.

Bug:  716571 ,  756564 
Change-Id: I541c8e181fadaf58710da57b6e9f5e8971451073
Reviewed-on: https://chromium-review.googlesource.com/619170
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496219}
[modify] https://crrev.com/09b107130f5c7a4cb377322b879ac2aac67cadbf/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/09b107130f5c7a4cb377322b879ac2aac67cadbf/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
[modify] https://crrev.com/09b107130f5c7a4cb377322b879ac2aac67cadbf/third_party/WebKit/Source/modules/vr/VRDisplay.h

Michael, is this something that I can verify manually? It sounds like I can, but I'm not sure what the details would be. Thanks.

We would need a test page that tries to play video during the vrdisplayactivate event. We should fix the video test page on webvr.info to do this.