Remove _wp_upload_dir_baseurl()

[azaozz]

This is a follow up from #36371.

_wp_upload_dir_baseurl() is a private function introduced in 4.4 as part of the "responsive images" feature. It was for runtime caching of the URL to the uploads directory. It is deprecated in 4.5 with the introduction of wp_get_upload_dir(), and currently it is only used in an older version of the feature plugin.

[joemcgill]

We missed this at the end of 4.5. Going to see if we can make this happen in 4.6.

[azaozz]

Replying to joemcgill:

If still no calls to it in the plugins directory, I'd go for it now (the sooner, the better).

[kirasong]

Let's do it.

[joemcgill]

Remove deprecated _wp_upload_dir_baseurl() from core.

[joemcgill]

36375.diff​ removes this function from core. I checked the feature plugin, RICG Responsive Images plugin, which is the only place this is used outside of core, and there it is used as part of a back-compat shim that only gets loaded on pre-4.4 versions of WordPress. The plugin also includes its own version of this function definition for those cases as well, so it is safe to remove from core without any changes to the plugin.

[kirasong]

+1

[joemcgill]

In 37676:

Media: remove _wp_upload_dir_baseurl().

_wp_upload_dir_baseurl() is a private function introduced in 4.4
as part of the "responsive images" feature. It was for runtime
caching of the URL to the uploads directory. It is deprecated in
4.5 with the introduction of wp_get_upload_dir().

Outside core, it's only used as part of a back-compat shim in the
original feature plugin for responsive images (ricg-responsive-images),
which includes its own version of the function definition, so it's
safe to remove from core.

Fixes #36375.