App leads to ANR after removing account if there were too many downloaded files

[jesmrec]

Steps to reproduce

1. Download a big amount of files (i used 3GB) in the oC app
2. Remove the accounts in the Manage Accounts menu

Actual behaviour

App freezes during the time it takes to remove all the files. After some seconds, ANR dialog (could) appear

Expected behaviour

Set kind of spinner/waiter, so the user knows that app is working internally

This is a 2.19 regression

[jesmrec]

Developing a worker could be a good solution.