Hopefully they'll move their own products to use the solution built into mobile chrome [0]. I hope that this "official" way of prompting users isn't penalised. The engagement logic is in the browser and as a developer you can't override it and force it to show. It makes testing it interesting! I dug into the code and wrote up my findings in a couple of blog posts [1].
Edit: In case it's not clear, this isn't just for web apps. As of at least a month ago (Chrome 44) you can add native app install banners to a website [2].
[0] https://developers.google.com/web/updates/2015/03/increasing...
[1] https://unop.uk/dev/experience-with-mobile-chrome-app-instal...
Edit: In case it's not clear, this isn't just for web apps. As of at least a month ago (Chrome 44) you can add native app install banners to a website [2].
[2] https://developers.google.com/web/updates/2015/03/increasing...