Script loader: simplify maintenance

[azaozz]

The main functionality of script-loader is to provide a list of all WordPress scripts and stylesheets together with their dependencies, translation objects and extra/inline code.

During the WP 5.0 development a few (shorthand) functions were introduced that output hard-coded data used to "construct" that list by running several loops instead of the simpler, one-line definitions like in the pre-existing list. This makes it harder to "see" and maintain the entries in the list, and doesn't bring any benefits (all data is still hard-coded, but is now in separate places). It also makes it harder to "dynamically" extract and construct the scripts list like in #48154.

For best results and easier maintenance the "helper functions" introduced in WP 5.0 should be removed and the list of scripts in wp_default_scripts () should include all entries.

[azaozz]

Looks like an exception would be wp_tinymce_inline_scripts() as it duplicates some of the functionality from class-wp-editor.php, but worth another look at how to do that better.

Another case to try to improve is outputting the polyfills (get rid of document.write, etc.).

[davidbaumwald]

@azaozz Is this still doable for 5.5?

[azaozz]

This is still mostly TBD. Lets move it to future release.