Native app install banner not showing

Hello, I'm trying to add a native app install banner like shown [here](https://developers.google.com/web/updates/2015/03/increasing-engagement-with-app-install-banners-in-chrome-for-android)

My manifest file looks like [this](http://storage8.static.itmages.com/i/16/0706/h_1467821105_6821380_d1e2590ee4.png)

I know that my file is parsed by chrome because if I make a mistake inside the json file on purpose, it gives an error like this : "App banner not shown: play1 application is not supported on Android"

I'm also using https, so I don't see what could be the problem.
However, I don't have a service worker registered, because in the docs, it says, to add a native app install banner :
"The criteria are similar to the Web App install banner except for the need of a Serivce Worker:"
So I guess I don't need to create a service worker for this to work right ?

EDIT : please delete or close this issue, I created a new one aiming at the real problem here