WPT/dev testability: Create way to test features related to / currently dependent on install #1194
Description
There is no way to test the following things, for web platform tests or developer
- Display-mode css media query to detect PWA display mode.
- install detection features (which have non-standardized methods today, planning on standardization (Issue Way to detect if a web app is installed #1092)
- Having the parsed manifest be “read” to understand how each browser applies the manifest to the installed web app experiences.
- e.g. test to make sure the manifest id doesn't change for devs. WPT test to make sure we resolve the manifest id correctly. etc.
- App update behavior testing - did the app metadata update? (this likely can follow easily from the above point, but might need a bit of extra test infra to allow tests to wait for this to finish)
- Maybe: check the final OS-given information - icons, name, etc?
Chromium features:
- Handling of links clicks (going into an installed web app experience vs outside). Mostly for testing navigation management, which is mostly Chromium-only. But Safari certainly also has behavior of 'when does a link click from an app go back to browser vs stay in app)
- protocol handlers handling protocol link launches
- file handlers, handling file launches