Profile / Container support on Android

[kingdomh-ideas]

Hey, wanted to float this idea and see if there's interest from @uazo and the community.

The problem

On desktop, every major browser lets you run separate profiles — isolated cookies, history, bookmarks, extensions. On Android, nothing does this. Chrome limits you to one profile. Firefox Containers don't exist on mobile. No Chromium fork has built it either.
Right now the only workaround is running 3-4 separate browser apps side by side, which works but isn't great. There's been demand for this for a while — Ask HN thread, Android Authority workarounds, etc. Also see pawxy browser++ feature.

What I'd want to build

The good news is Chromium already has the full profile backend (ProfileManager, ProfileKeyedServiceFactory, per-profile data directories) working on desktop. Google just #ifdef'd it out for Android. So the work is mostly:

1. Re-enable the existing profile infrastructure for Android builds
2. Add a minimal Android UI — profile picker, toolbar indicator showing which profile is active
3. Each profile gets its own data subdirectory (Default/, Profile 1/, etc.) with isolated state
4. Wire it up via Chromium's existing JNI bridge patterns

Later, multi-instance support (FLAG_ACTIVITY_MULTIPLE_TASK) for DeX / split-screen, and per-profile extension sets once extensions are stable.

Questions

• Does this fit Cromite's scope, or is it out of bounds?
• Any guidance on patch structure / conventions I should follow?
• Should this be independent of the extension work or integrated with it?

I use 4 browser profiles on desktop daily (personal + multiple businesses) and I'm on a Galaxy Z Fold 6 running DeX regularly. This is a problem I'd use the solution to every day, and I'm willing to put in the work to learn the codebase and submit patches.
Happy to hear thoughts from anyone who'd use this or has ideas on the approach.