Add /chrome page for Chrome Canary (Windows, OpenVR) support

[cvan]

Instructions

0. Ensure Steam VR is installed.
1. Download Chrome Canary (for Windows)
2. In the URL bar, load chrome://flags to enable the following flags:
   • WebVR: chrome://flags#enable-webvr
   • OpenVR: chrome://flags#openvr
   • Gamepad Extensions: chrome://flags#enable-gamepad-extensions
3. Enjoy WebVR content!

Supported headsets

• Windows Mixed Reality (tested with Dell Visor)
• HTC Vive
• Oculus Rift (with Touch controllers)

Known issues

TBD

FAQ

Q. There's an active Origin Trial for WebVR on Chrome for Android. Will there be a separate Origin Trial for desktop WebVR support?
A. …

Q. What's the overlap with WebVR and WebXR on desktop?
A. …

Q. Where do I file issues?
A. Chromium issue tracker? Elsewhere?

Q. How do I troubleshoot, find issues?
A. WebVR Slack? Twitter?

/cc @jpmedley @toji