code: private PorterDuffColorFilter createTintFilter(ColorStateList tint, PorterDuff.Mode tintMode) {
          if (tint == null || tintMode == null) {
              return null;
          }
          final int color = tint.getColorForState(getState(), Color.TRANSPARENT);
          return new PorterDuffColorFilter(color, tintMode);
      }
docs: Ensures the tint filter is consistent with the current tint color and
  mode.