when using module/nomodule make sure to use modulepreload instead of preload for the priority hint

[erwinmombay]

Currently chrome double downloads the module (mjs) script twice when we use preload instead of modulepreload in Chrome. Safari does not support modulepreload unfortunately but this is the tradeoff we are making

[CLAassistant]

All committers have signed the CLA.

[sebastianbenz]

Thanks for the fix! How long does it take for the validator changes to go live?

[erwinmombay]

i believe @honeybadgerdontcare is working on the validator changes so he'll have a more accurate timeline than i can estimate.

[honeybadgerdontcare]

It's in cl/363067094 and will be live this week or early next.

[erwinmombay]

this will be temporary and we will most likely need to revert back to preload at some point, should we leave this PR as is or have some sort of mechanism in place to toggle this in the optimizer?

[honeybadgerdontcare]

Temporary is between now and earliest May. Even then some users may not upgrade to the latest, correct? In that case it may be a bit longer, but I would think this could be reverted instead of toggled when that version of Chrome is widely adopted.

It'll continue to be supported in the validator regardless.

[sebastianbenz]

OK, I'll merge this PR once validator changes are live. We can revert behaviour in a subsequent release.

[sebastianbenz]

Just verified in the AMP Validator that it's now valid AMP.