closes: CNVS-32934
see
https://developers.google.com/web/updates/2015/03/increasing-engagement-with-app-install-banners-in-chrome-for-android#native
for how these work.
test plan:
* you have to be serving canvas over https://
* on android, install Chrome, or another browser that
supports Service Workers and manifest
* Visit the site over two separate days.
* Or, more usefully, enable chrome://flags/#bypass-app-banner-engagement-checks
* it should ask you to install the native canvas android app
Change-Id: I7c5cf8e9ecffd4dc52058bed865f82eaf3a7ea97
Reviewed-on: https://gerrit.instructure.com/93760
Reviewed-by: Simon Williams <simon@instructure.com>
Tested-by: Jenkins
QA-Review: Benjamin Christian Nelson <bcnelson@instructure.com>
Product-Review: Ryan Shaw <ryan@instructure.com>
Ryan Shaw