What steps will reproduce the problem?
(1) Don't have killer-marmot.appspot.com/web installed.
(2) Visit: killer-marmot.appspot.com/web

What is the expected result?

Option to install Killer Marmot should appear in omnibox.

What happens instead?

You have to open the Chrome menu to see that this is an installable site.

Slides: https://docs.google.com/presentation/d/1hBKxbAt8Lv6fjHyp97PqLamCIXlSIF_sMmWyZnMob7M/edit#slide=id.g3ecc7c0b71_0_0