In spite all of this, Android Team has given zero support for anything other than Java on Android, even for its own languages.
The NDK is anemic, because "In general, you should only use the NDK if it is essential to your app—never because you simply prefer to program in C/C++. When examining whether or not you should develop in native code, think about your requirements and see if the Android framework APIs provide the functionality that you need."
http://developer.android.com/tools/sdk/ndk/index.html
And the Go and Dart teams had to work on their own even for the NDK integration.
The results of their work aren't even described in any of the official Android documentation sites.