1425867 - Crash after specific steps after enabling "Close Private Tabs when leaving private browsing"

Status: NEW

(Firefox for iOS :: General, defect, P5)

Description

[Simon Basca [:SimonB]]

Attachment: Client-2017-12-18-183755.ips.beta

Build: 10.4 (8288)
Device: iPhone 8
iOS: 11.0.3

Pre-requisites:
- From Setting, enable "Close private tabs when leaving private browsing" 

Steps to reproduce:
1. Open a Tab in Private Browsing
2. Open Tabs Tray
3. Use a Swipe gesture to close the tab but do not lift the finger
4. Tap the mask button to switch to normal browsing
5. Repeat step 4) after a few seconds if the view is not switched to normal browsing after the first tap on the mask button
7. Release the swipe gesture to close the tab in normal browsing

Actual results:
- Firefox will crash after releasing the swipe gesture to close the tab in normal browsing. 

See video here:
- https://www.youtube.com/watch?v=SmKxUcps1Yw