WebvttCssStyle.FontSizeUnit (ExoPlayer library)

```
@Documented
@Retention(SOURCE)
@Target(TYPE_USE)
public static @interface WebvttCssStyle.FontSizeUnit
```
Font size unit enum. One of WebvttCssStyle.UNSPECIFIED, WebvttCssStyle.FONT_SIZE_UNIT_PIXEL, WebvttCssStyle.FONT_SIZE_UNIT_EM or WebvttCssStyle.FONT_SIZE_UNIT_PERCENT.