Remember temporarily whitelisted sites after updates #717

Prerequisites

• I verified that this is not a filter issue
  • Filter issues MUST be reported at filter issue tracker
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uBlockOrigin
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported.
• I tried to reproduce the issue when...
  • uBlock Origin is the only extension
  • uBlock Origin with default lists/settings
  • using a new, unmodified browser profile
• I am running the latest version of uBlock Origin
• I checked the documentation to understand that the issue I report is not a normal behavior

Description

If dynamic filtering is used and uBlock Origin is updated while various sites are temporarily whitelisted, these sites are no longer temporarily whitelisted after the update. For long running browser sessions with many tabs open and multiple projects going on, this is quite annoying.

A fix is of course to disallow automatic updates under the uBlock Origin extension settings, but I will then probably forget about checking for updates manually and I like the updating to take care of itself.

I don't know if it can be done at all, but a nice enhancement is if uBlock Origin would not forget about the temporarily allowed stuff after an update.

Just to be clear, I temporarily allow some sites, because I don't want to permanently whitelist them. After the update, the sites should still just be temporarily whitelisted.

A specific URL where the issue occurs

https://www.google.com/

Steps to Reproduce

1. Enable dynamic filtering and temporarily whitelist a site.
2. Wait for uBlock Origin to update to a newer version.

Expected behavior:

uBlock Origin will still remember the temporarily whitelisted site after the update.

Actual behavior:

uBlock Origin does no longer remember the temporarily whitelisted site after the update.

Your environment

• uBlock Origin version: 1.22
• Browser Name and version: Mozilla Firefox 68.0.2