Add crossOrigin via props to _document Head and NextScript

[Enalmada]

This alternative implementation of #5150 follows @timneutkens suggestion of using props.

Fixes #5150
Fixes #3630

[timneutkens]

The PR looks great! The only thing missing is a test for this new behavior.

[timneutkens]

You can add this test to test/integration/app-document by checking the HTML response

[Enalmada]

Ah yes, good idea. Thanks for telling me which one, that was very helpful. Tests do not seem to work on windows for me but I was able to WSL them following this: https://github.com/zeit/next.js/blob/canary/contributing.md

Unfortunately the tests seem to fail on CircleCI but pass fine on my local machine:

I am sure that CircleCI is correct but it is just so strange I get passing. If you could help me understand why you think the test is failing it might help me figure out why it is passing on my machine.

[Enalmada]

Thanks for your help. I will spend some time figuring out how to get my tests working right.

[timneutkens]

Great PR @Enalmada!

[jclem]

Thank you @timneutkens and @Enalmada! Can't wait to see this in a release 🎉

[timneutkens]

@jclem didn't know you were running into this at GitHub 😄 Feel free to DM me on spectrum/twitter if you run into specific issues.