[Bug] Custom Tab does not restore itself when recreated

[jonalmeida]

Steps to reproduce

1. (Optional for easy reproducibility) Set Developer options > Background process limit to 'No background processes'.
2. Open a custom tab (and don't close it at the next step).
3. Do other things, use other memory-intensive apps.
4. Return to the custom tab.

Expected behavior

1. The custom tab is loaded (or it shows [Bug] Blank tab after keeping custom tab open and switching to off an android permission. #2383)

Actual behavior

1. The custom tab shows a completely blank page with a greyed out section on the bottom where the BrowserToolbar was.

Device information

• Android device: Android 9 (Pixel 2)
• Fenix version: 9b633f7 (master)

1.0.1935 (Build #1)
📦: 10.0.1, a573b4116
🦎: 69.0-20190824140027

┆Issue is synchronized with this Jira Task

[jonalmeida]

We have a fix for #2383 but I'm unable to verify if it works because of this other bug. The fix I'm trying to test: mozilla-mobile/reference-browser#894

See this a-c issue for technical history of it: mozilla-mobile/android-components#3773

This is also no related to #2383 since the Custom Tabs code never gets invoked when returning to the Custom Tab, so it seems to be something else unrelated to the lifecycle of the app.

[lobontiumira]

Verified on the latest Nightly build from 2/24, and, with:

• Samsung Galaxy Note 8 (Android 9), Nokia 6 (Android 7.1.1), Sony Xperia Z5 Premium (Android 7.1.1) - I could not reproduce the issue,
• however, with Google Pixel (Android 10), after step 4, the custom tab showed a completely blank page. I've opened a custom tab in gmail, minimized it, opened Reddit, went back to gmail.

Please see the attached logcat from Google Pixel:

logcat.txt

I'll remove the qa-needed label for now.

[stale]

See: #17373 This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.