Some time ago I built something similar to Ejecta (https://github.com/funkaster/FakeWebGL) aiming to have support for Android. It's using Spidermonkey instead of ScriptingCore, and it's written in C++. I haven't updated the code in a long time, but it shouldn't be too hard to update to the newer SpiderMonkey and at some point add Android support :) I just need the time (which between work and my side projects, is almost 0). If someone wants to help, the code is there, and I'll be happy to provide guidance and support.