Решение
в процессе владельца
final SharedPreferences pref = getSharedPreferences("preferences", Context.MODE_WORLD_READABLE | Context.MODE_WORLD_WRITEABLE | Context.MODE_MULTI_PROCESS);
final SharedPreferences.Editor edit = pref.edit();
edit.putInt(....)
edit.commit();
в другом процессе
final Context remoteContext = createPackageContext(OWNER_PACKAGE_NAME, Context.CONTEXT_IGNORE_SECURITY);
final SharedPreferences pref = remoteContext.getSharedPreferences("preferences", Context.MODE_WORLD_READABLE | Context.MODE_WORLD_WRITEABLE | Context.MODE_MULTI_PROCESS);
pref.getInt(...)