4a0e4153eb
This updates `wp_get_loading_optimization_attributes()` and `wp_maybe_add_fetchpriority_high_attr()` to account for cases where an `IMG` has `fetchpriority=low` or `fetchpriority=auto`: * `IMG` tags with `fetchpriority=low` are not lazy-loaded since they may be in a Navigation overlay, Details block, or Accordion Item block and need to be loaded the instant the user toggles the block. * `IMG` tags with `fetchpriority=auto` do not increase the media count since they may be hidden in a viewport by block visibility settings. * Blocks with conditional visibility (such as hidden on mobile or desktop) now automatically add `fetchpriority="auto"` to their contained `IMG` tags to prevent them from erroneously receiving `fetchpriority=high` or affecting the lazy-loading of subsequent images. * An `IMG` with `fetchpriority=auto` which also surpasses the `wp_min_priority_img_pixels` threshold will prevent a subsequent image from getting `fetchpriority=high`. Developed in https://github.com/WordPress/wordpress-develop/pull/11196 Includes backport of [https://github.com/WordPress/gutenberg/pull/76302 Gutenberg#76302]. See related Gutenberg issues: - [https://github.com/WordPress/gutenberg/issues/76181 76181]: Image in navigation overlay can get `fetchpriority=high` and degrade LCP metric for page. - [https://github.com/WordPress/gutenberg/issues/76268 76268]: Image in collapsed Details block may erroneously get `fetchpriority=high` even though hidden. - [https://github.com/WordPress/gutenberg/issues/76301 76301]: Block Visibility: `IMG` in viewport-conditional block may get `fetchpriority=high` even when not displayed. - [https://github.com/WordPress/gutenberg/issues/76335 76335]: Image in collapsed Accordion block may erroneously get `fetchpriority=high` even though hidden. Follow-up to r56347, r56037. Props westonruter, mukesh27, ramonopoly, wildworks. See #58235. Fixes #64823. Built from https://develop.svn.wordpress.org/trunk@61934 git-svn-id: http://core.svn.wordpress.org/trunk@61216 1a063a9b-81f0-0310-95a4-ce76da25c4cd