MU WPCOM: Port hide-homepage-title feature from ETK (#38190)

* MU WPCOM: Port hide-homepage-title feature from ETK

* changelog

projects/packages/jetpack-mu-wpcom/changelog/mu-wpcom-hide-homepage-title

@@ -0,0 +1,4 @@
+Significance: patch
+Type: added
+
+MU WPCOM: Port the hide-homepage-title feature from ETK

projects/packages/jetpack-mu-wpcom/src/class-jetpack-mu-wpcom.php

@@ -94,6 +94,7 @@ public static function load_features() {
 		if ( ! class_exists( 'A8C\FSE\Help_Center' ) ) {
 			require_once __DIR__ . '/features/help-center/class-help-center.php';
 		}
+		require_once __DIR__ . '/features/hide-homepage-title/hide-homepage-title.php';
 		require_once __DIR__ . '/features/import-customizations/import-customizations.php';
 		require_once __DIR__ . '/features/marketplace-products-updater/class-marketplace-products-updater.php';
 		require_once __DIR__ . '/features/media/heif-support.php';

projects/packages/jetpack-mu-wpcom/src/features/hide-homepage-title/hide-homepage-title.css

@@ -0,0 +1,3 @@
+body.hide-homepage-title .editor-post-title {
+	opacity: 0.4;
+}

projects/packages/jetpack-mu-wpcom/src/features/hide-homepage-title/hide-homepage-title.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * Allow homepage title to be edited even when hidden Lighter color to signify not visible from front page
+ *
+ * @package automattic/jetpack-mu-wpcom
+ */
+
+use Automattic\Jetpack\Jetpack_Mu_Wpcom;
+
+define( 'MU_WPCOM_HOMEPAGE_TITLE_HIDDEN', true );
+
+/**
+ * Can be used to determine if the current screen is the block editor.
+ *
+ * @return bool True if the current screen is a block editor screen. False otherwise.
+ */
+function wpcom_is_block_editor_screen() {
+	return is_callable( 'get_current_screen' ) && get_current_screen() && get_current_screen()->is_block_editor();
+}
+
+/**
+ * Detects if the current page is the homepage post editor, and if the homepage
+ * title is hidden.
+ *
+ * @return bool True if the homepage title features should be used. (See above.)
+ */
+function wpcom_is_homepage_title_hidden() {
+	global $post;
+
+	// Handle the case where we are not rendering a post.
+	if ( ! isset( $post ) ) {
+		return false;
+	}
+
+	$hide_homepage_title = (bool) get_theme_mod( 'hide_front_page_title', false );
+	$is_homepage         = ( (int) get_option( 'page_on_front' ) === $post->ID );
+	return (bool) wpcom_is_block_editor_screen() && $hide_homepage_title && $is_homepage;
+}
+
+/**
+ * Adds custom classes to the admin body classes.
+ *
+ * @param string $classes Classes for the body element.
+ * @return string
+ */
+function wpcom_add_hide_homepage_title_class_if_needed( $classes ) {
+	if ( wpcom_is_homepage_title_hidden() ) {
+		$classes .= ' hide-homepage-title ';
+	}
+
+	return $classes;
+}
+add_filter( 'admin_body_class', 'wpcom_add_hide_homepage_title_class_if_needed' );
+
+/**
+ * Enqueue assets
+ */
+function wpcom_enqueue_hide_homepage_title_assets() {
+	if ( ! wpcom_is_homepage_title_hidden() ) {
+		return;
+	}
+
+	wp_enqueue_style(
+		'wpcom-hide-homepage-title',
+		plugins_url( 'hide-homepage-title.css', __FILE__ ),
+		array(),
+		Jetpack_Mu_Wpcom::PACKAGE_VERSION
+	);
+}
+add_action( 'admin_enqueue_scripts', 'wpcom_enqueue_hide_homepage_title_assets' );