A quick look at their code samples reveals the issue samples - as browsers have not yet standardized the syntax, in order to use this feature you need to use versions of the CSS property names with browser-specific prefixes for example (for Firefox) "-moz-font-feature-settings" instead of just "font-feature settings". For some reason, this demo doesn't include the "-webkit"-prefixed versions - might be they don't exist, might be Microsoft's people just didn't think to.
That was exactly my question: is this one of those rare cases where IE10 is "ahead" of Webkit (and thus Chrome)? The fact that Firefox supports it too rules out the notion that this could just be some crackpot Microsoft-only technology like DX transforms. My question remains: does Webkit not yet support this?