A similar question has been asked before, but had no traction. Clearly, it is possible but it is by no means clear how to do it in our own non-tabris Android app.
The best documentation we have on the matter is this commit, but I tried V8.setFlags("--expose-debug-as=Debug"); as well as V8.setFlags("--expose-debug-as=" + DebugHandler.DEBUG_OBJECT_NAME); but no debuggable app appeared in chrome developer tools.
I even tried in combo with enabling Stetho and in that case I was able to debug the app, but there was no javascript source to debug. I believe that I'm close but missing one small crucial nugget.
The article that you link to states that they implemented it in their product using the Stetho library to provide the Chrome Dev Tools debugger protocol support. Therefore you would need to use the DebugAPI class and expose that to DevTools via the Chrome debug bridge protocol, though at first glance I can't see how to use Stetho to expose the debug api.
The tests in the j2v8 codebase do provide a good example of how to use the DebugAPI