[GB-Mobile Integration] Fix for Backspace does not outdent nested list item

[daniloercoli]

This PR is the first step required to fix https://github.com/wordpress-mobile/gutenberg-mobile/issues/1027

@mkevins has reported the problem with backspace and nested lists, and already proposed a solution here. In this PR I started from scratch, but ended up with similar code.

Please, test this PR by pointing the experimental branch here https://github.com/wordpress-mobile/gutenberg-mobile/tree/experimental/fix-backspace-outdent-on-nested-lists to the full hash fbf98c1af64552a01f1ae203d295b79b8362c629 of this branch.

• Test both the Google GBoard and the AOSP keyboard.
• Also test on real devices, and emulators by using the external OS keyboard as input (in order to simulate HW keyboard).

Review

@mkevins

Note: I run both kotlin unit tests, and Java connected tests on this PR without finding any issue.

[mchowning]

👋 @daniloercoli ! I'm assuming we should still work to merge this PR since the related issue is still open. Do you agree @mkevins, @daniloercoli ?

[mkevins]

@daniloercoli ! I'm assuming we should still work to merge this PR since the related issue is still open. Do you agree @mkevins, @daniloercoli ?

Hi @mchowning :wave: :smile:

I somehow missed the original ping and just saw this one, so my apologies for the long delay. I agree, this is worth pursuing. I'm not sure off-hand whether the proposed solution needs to be updated to be current with all the changes from then to now. Do you have an idea of the priority of the original issue?