MB 20: Allow packaged-addons in PBM.

We install a few addons from the distribution directory, but they are
not automatically enabled for PBM mode.
This commit modifies the code that installs them to also add the PBM
permission to the known ones.

toolkit/mozapps/extensions/internal/XPIProvider.jsm

@@ -45,6 +45,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
 });
 
 XPCOMUtils.defineLazyModuleGetters(lazy, {
+  ExtensionPermissions: "resource://gre/modules/ExtensionPermissions.jsm",
   XPIDatabase: "resource://gre/modules/addons/XPIDatabase.jsm",
   XPIDatabaseReconcile: "resource://gre/modules/addons/XPIDatabase.jsm",
   XPIInstall: "resource://gre/modules/addons/XPIInstall.jsm",
@@ -2990,6 +2991,19 @@ var XPIProvider = {
             }
             aManifests[loc.name][id] = addon;
             changed = true;
+
+            // mullvad-browser#20: Allow pre-installed extensions in PBM
+            const PRIVATE_ALLOWED_PERMISSION =
+              "internal:privateBrowsingAllowed";
+            if (
+              addon.id === "uBlock0@raymondhill.net" ||
+              addon.id == "{d19a89b9-76c1-4a61-bcd4-49e8de916403}"
+            ) {
+              lazy.ExtensionPermissions.add(addon.id, {
+                permissions: [PRIVATE_ALLOWED_PERMISSION],
+                origins: [],
+              });
+            }
           }
         } catch (e) {
           logger.error(`Failed to install distribution add-on ${file.path}`, e);