private AppCompatDelegate getDelegate() {
    if (delegate == null) {
      delegate = AppCompatDelegate.create(this, null);
    }
    return delegate;
  }
A {@link android.preference.PreferenceActivity} which implements and proxies the necessary calls
to be used with AppCompat. Largely inspired from the AOSP support-v7 demos.
java/com/google/android/apps/authenticator/settings/AppCompatPreferenceActivity.java