How to programatically refresh chrome policy 'ExtensionInstallBlacklist' on windows?

I need to update the Chrome policy 'ExtensionInstallBlacklist' from a desktop application on windows. Im already able to modify the policy through the registry by adding values to HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExtensionInstallBlacklist.

However, to have an effect in chrome, I need to manually visit chrome://policy/ within Chrome and hit the "refresh policies"-button.

What I already tried:

• According to this other question on SO, one can use gpupdate /force to trigger a reaload of Chrome policies. I tried gpupdate and gpupdate /force, both inside an admin cmd and inside a normal user cmd - no effect.

Is there another way to programatically tell Chrome to reload the policies or did I miss something with the gpupdate-solution?

EDIT:

These are the changes I've made:

• Adding the key value pair 1:cfhdojbkjhnklbpkdaibdccddilifddb to HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\ExtensionInstallBlacklist(it's the id of Adblock Plus)