fixup! Bug 42027: Base Browser migration procedures.

Bug 43124: Implement a migration procedure for Android.

mobile/shared/components/geckoview/GeckoViewStartup.sys.mjs

@@ -259,6 +259,8 @@ export class GeckoViewStartup {
           "GeckoView:InitialForeground",
         ]);
 
+        this.#migratePreferences();
+
         Services.obs.addObserver(this, "browser-idle-startup-tasks-finished");
         Services.obs.addObserver(this, "handlersvc-store-initialized");
 
@@ -365,6 +367,50 @@ export class GeckoViewStartup {
         break;
     }
   }
+
+  /**
+   * This is the equivalent of BrowserGlue._migrateUITBB.
+   */
+  #migratePreferences() {
+    const MIGRATION_VERSION = 1;
+    const MIGRATION_PREF = "torbrowser.migration_android.version";
+
+    // We do not have a way to check for new profiles on Android.
+    // However, the first version is harmless for new installs, so run it
+    // anyway.
+    const currentVersion = Services.prefs.getIntPref(MIGRATION_PREF, 0);
+    if (currentVersion < 1) {
+      // First implementation of the migration on Android (tor-browser#43124,
+      // 14.0a5, September 2024).
+      const prefToClear = [
+        // Old torbutton preferences not used anymore.
+        // Some of them should have never been set on Android, as on Android we
+        // force PBM... But who knows about very old profiles.
+        "browser.cache.disk.enable",
+        "places.history.enabled",
+        "security.nocertdb",
+        "permissions.memory_only",
+        "extensions.torbutton.loglevel",
+        "extensions.torbutton.logmethod",
+        "extensions.torbutton.pref_fixup_version",
+        "extensions.torbutton.resize_new_windows",
+        "extensions.torbutton.startup",
+        "extensions.torlauncher.prompt_for_locale",
+        "extensions.torlauncher.loglevel",
+        "extensions.torlauncher.logmethod",
+        "extensions.torlauncher.torrc_fixup_version",
+        // tor-browser#42149: Do not change HTTPS-Only settings in the security
+        // level.
+        "dom.security.https_only_mode_send_http_background_request",
+      ];
+      for (const pref of prefToClear) {
+        if (Services.prefs.prefHasUserValue(pref)) {
+          Services.prefs.clearUserPref(pref);
+        }
+      }
+    }
+    Services.prefs.setIntPref(MIGRATION_PREF, MIGRATION_VERSION);
+  }
 }
 
 GeckoViewStartup.prototype.classID = Components.ID(