I'd say it's a chrome issue, I also had the issue, and then it disappeared, and re-appeared again.
However, it works fine in chrome stable, beta and canary.
We won't actively debug an issue that doesn't exist in a stable (or beta/alpha) browser.
So far, we found the 29 august version to be the more stable one, so you might give it a try (I just tried it and also had the same INSECURE_RESPONSE ssl issue though...).
If someone has a temporary workaround, we are interested too :).
Browser vendors are working actively on webvr, so changes and improvements are soon to be expected.