Either the polyfills aren't being shipped or their feature detection is broken, because I get "document.registerElement is not a function" in Firefox Nightly wi

Either the polyfills aren't being shipped or their feature detection is broken, because I get "document.registerElement is not a function" in Firefox Nightly with a spoofed UA string, and I get marginally further if I turn on our experimental native support for Web Components: http://imgur.com/a/TgnrQ http://imgur.com/a/TgnrQ