Fenix: [Bug] Crash when opening tab from collection

[csadilek]

New crash in Nightly that needs investigation:
https://sentry.prod.mozaws.net/operations/fenix-nightly/issues/6326356/

Happens quite frequently, but can not reproduce yet.

[csadilek]

STR:

• Open a page
• Open any link on the page using the context menu (e.g. open in new tab) to open a "child" tab
• Switch to home fragment and store child tab in a collection
• Close the parent tab

From here on, Fenix will crash every time the child tab is (re-)opened from its collection, as it is stored with the ID of its parent, which doesn't exist anymore.

In A-C, we update the parent ID of all tabs when the parent is deleted, but this does not apply to the collection state (which is a copy).

Possible solutions:

• Be tolerant when adding sessions and ignore the fact that the parent could no longer be there
• Update the collection state to remove the parent ID when it is deleted
• Don't restore the parent ID for collection items / tabs. Do we really need the parent ID for collections?

[csadilek]

This is fixed in A-C and should no longer be reproducible in the next Nightly.

[softvision-miralobontiu]

Verified as fixed with the latest Nightly build from Play Store 190925 (#12681805) with Huawei Honor 8 (Android 7), and Samsung Galaxy Note 8 (Android 9). The app didn't crash, following the steps provided.