@Override
        public void onPageSelected(int position) {
          // If user is not in the last page, we show the "Skip" button and the "Next" button.
          // On the last page we hide the "Skip" and "Next" button, only show the "Done" button.
          if (position < getViewPagerTotalItem() - 1) {
            buttonSkip.setVisibility(View.VISIBLE);
            buttonNext.setVisibility(View.VISIBLE);
            buttonDone.setVisibility(View.GONE);
          } else {
            buttonSkip.setVisibility(View.GONE);
            buttonNext.setVisibility(View.GONE);
            buttonDone.setVisibility(View.VISIBLE);
          }
        }
Finish current {@link HowItWorksActivity}. If we are on the very first onboarding experience,
proceed to the {@link AddAccountActivity}.
java/com/google/android/apps/authenticator/howitworks/HowItWorksActivity.java