Easy: it's Javascript and canvas 2D packaged with https://crosswalk-project.org/ https://crosswalk-project.org/ ; and 4.0 is a requirement. I was willing to us

Easy: it's Javascript and canvas 2D packaged with https://crosswalk-project.org/ https://crosswalk-project.org/ ; and 4.0 is a requirement. I was willing to use a WebView with Cordova, but Kit Kat introduced a bug (not hw acceleration in canvas 2D!) and I was getting 2 FPS instead of the expected 30. Crosswalk works pretty well, although has the inconvenient of being a native component.