Crash after opening from external source

[sblatz]

Steps to reproduce

1. Navigate to a website from within Fenix
2. While BrowserFragment is open, close the app
3. Open a link from an external source (I used Samsung messages)
4. Press Home
5. Open the tab you previously opened

Expected behavior

Tab loads normally

Actual behavior

Fenix crashes

Crash log

Device information

• Android device: 8.0.0
• Fenix version: 1.0.19090 (master)

┆Issue is synchronized with this Jira Task

[sblatz]

Perhaps related to #575

Looping in @colintheshots on this since he just resolved the issue in #575.

From @colintheshots:

I resolved the recreate on custom tabs issue by not recreating if the theme was already set correctly. It might be a new way to recreate or create two GeckoViews for the same session.

[sblatz]

I confirmed that the activity is not being recreated in this circumstance.

What's odd is that going home, then selecting the newly created tab (that came from an external source) does not cause a crash. This ticket will require more investigation and will likely have to be pushed to next sprint unless someone else can take it over

[sblatz]

It seems like abd0845 initially fixed this, but with the change at cf260e4 the crash returned.

@pocmo any thoughts on this?

[sblatz]

I paired with @boek for a bit. Turns out we needed to make our activity a singleInstance

Basically when we were launching from outside the app, a new HomeActivity was created while still keeping the old one around, which meant bad memory states could happen leading to crashes.
More info here.

[sblatz]

Note: our incoming patch will also fix an issue where opening from an external app would actually create the activity inside your current app rather than sending you off to Fenix (not a custom tab).