Tweak web font loading, so that: - Web fonts with 'font-display: optional' never cause relayout - Web font preloading is allowed to slightly block rendering (for all font-display values), so that if the font loads fast enough, we don't need to render with fallback. Therefore, when 'font-display: optional' and preloading are used together, we'll never see layout shifting from font swapping, and still have a good chance to use the font if it loads fast enough (e.g., from disk cache).
Relayout after font loading is an issue, as it leads to unstable layout, and increases the latency for the font to show up. Now that CSSWG has reached a resolution to avoid that, our implementation should catch up.
Docs: https://bit.ly/36E8UKB
Explainers: https://bit.ly/2FELF7e