@Override
  public SharedPreferences getSharedPreferences(String name, int mode) {
    return super.getSharedPreferences(mPrefix + name, mode);
  }
{@link ContextWrapper} that prefixes shared preference file names with the provided prefix and
passes all other invocations through unmodified to the delegate {@link Context}.
java/com/google/android/apps/authenticator/testability/SharedPreferencesRenamingDelegatingContext.java