I wonder if they could have just used CocoonJS, which is basically a reimplementation of WebView with better performance for games. But, anyway, yeah, it's well know the WebView on Android is a disaster. A top Facebook guy famously gave a key note at Android DevCon about why they switched to more native on mobile and said, "We don't hate the web [and HTML], we hate the webview." after going through countless bugs and…
At this point my question is the following: why on android and ios we have not a javascript/html5 -> native framework? I mean, the guys of windows phone made it. It is awesome and with great performance... why android and ios that came up in the market way before have still not implemented it?
Do you have some examples of this performance claim? Particularly games of the sort built with Unity? I've searched around and found no examples, though maybe I'm looking in the wrong places.
The other "walled garden" comments are curious, especially given that we're talking about Unity which can target just about anything with equal ease. Even going to raw metal, a significant portion of a game written for iOS can be easily ported to Android and the NDK, or Blackberry OS, or various other systems. The basic standards of C/C++, standard libraries, and OpenGL, mean that there is very broad "standardization".
For those who want cross-platform targeting, a cross-platform tool is critical - build an HTML5 app for Windows Phone and you have built an app that is just for Windows Phone. That it is built on web technologies is no more magical than being built on C++/OpenGL. There are tools like Intel's XDK if you want actual cross platform HTML5 support.