I saw a talk on FxOS (then B2G) earlier this year, and asked a question about how FxOS will handle native SDKs, considering practically every single mobile OS t

I saw a talk on FxOS (then B2G) earlier this year, and asked a question about how FxOS will handle native SDKs, considering practically every single mobile OS that used VMs to run apps had eventually capitulated and provided native SDKs for speed and codebase compatibility. The Mozilla guy who responded was very adamant on keeping HTML/CSS/JS the one and only dev environment for the OS. Perhaps JS optimization has come far enough that speed is not a problem, but how is FxOS going to handle codebase compatibility for bringing large preexisting native-code projects (eg. games) into it? Compiling the entirety of Unreal Engine 3 in Emscripten, for instance, seems a bit far-fetched.