@Override
      public void onClick(DialogInterface dialog, int id) {
        // If this activity is started from {@link AddAccountActivity}, open it again.
        if (mStartFromAddAccountActivity) {
          startActivity(new Intent(BarcodeCaptureActivity.this, AddAccountActivity.class));
        }
        finish();
      }
Handles the requesting of the camera permission.  This includes showing a "Snackbar" message of
why the permission is needed then sending the request.
java/com/google/android/apps/authenticator/barcode/BarcodeCaptureActivity.java