[MediaWiki] Allow delayStartupUntil=Configured without using inline config or query string

Created by: fred-wang

In MediaWiki, we'd like, the Startup should be delayed until MediaWiki has configured MathJax and downloaded MathJax's files with its own resource loader.

MathJax.js is loaded with MediaWiki's resource loader (which does not accept query string parameters). Ideally, MediaWiki folks don't want to have to insert an inline config that requires a call to eval.

An option would be to modify ConfigDelay so that

       var delay = this.params.delayStartupUntil || MathJax.Hub.config.delayStartupUntil || MathJax.delayStartupUntilConfigured;

That way, they can set MathJax = { delayStartupUntilConfigured: true } before loading MathJax.js.

I'm aware that it would add a non-standard way to configure MathJax but that's the simplest work around I can see. Any thoughts?