This still needs some discussion, but to help create an easier dev environment for working on UI features, we could get the Files App to run in a tab and access resources from a local Downloads directory. ARC++/Crostini/Drive would be disabled. This would NOT be used for testing or production use (except perhaps for issue 845818), but to make a short turnaroud dev environment that doesn't require re-building ChromeOS on each change.

This has already been prototyped in issue 845818. We need to investigate what part of that change is the APIs, how hard it would be to migrate these APIs to be available from other non-ChromeOS platforms, what effect it has on the code health, whether we can enable this only in a Debug build, and what the maintenance overhead of it would be if we only end up shipping the APIs on ChromeOS.

This could be used in combination with issue 849967 to get the Files App to run in a tab on Linux during development.