I'm preeettty sure that's just because it's relying on the separate WebView app, using WebView is also how it's possible for people to make sub-megabyte android browsers, such as [Naked Browser](https://play.google.com/store/apps/details?id=com.fevdev.nak...) and [Via](https://play.google.com/store/apps/details?id=mark.via.gp&hl...)

*correction, according to https://developer.chrome.com/multidevice/webview/overview they are still separate, it references android L dev preview so not the latest source tho...