MU WPCOM: Enable the custom-line-height feature for classic theme by …

…default (#38317)

* MU WPCOM: Enable the custom-line-height feature by default

* changelog

projects/packages/jetpack-mu-wpcom/changelog/mu-wpcom-custom-line-height

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+MU WPCOM: Enable the custom-line-height feature by default

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

@@ -132,6 +132,7 @@ public static function load_features() {
 	 * Can be moved back to load_features() once the feature no longer exists in the ETK plugin.
 	 */
 	public static function load_etk_features() {
+		require_once __DIR__ . '/features/block-editor/custom-line-height.php';
 		require_once __DIR__ . '/features/block-inserter-modifications/block-inserter-modifications.php';
 		require_once __DIR__ . '/features/hide-homepage-title/hide-homepage-title.php';
 		require_once __DIR__ . '/features/jetpack-global-styles/class-global-styles.php';

projects/packages/jetpack-mu-wpcom/src/features/block-editor/custom-line-height.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * Enable line-height settings for all themes with Gutenberg.
+ *
+ * @package jetpack-mu-wpcom
+ */
+
+define( 'MU_WPCOM_CUSTOM_LINE_HEIGHT', true );
+
+/**
+ * Prior to Gutenberg 8.6, line-height was always enabled, which meant that wpcom
+ * users had been utilizing the feature. With the 8.6 release, though, line-height
+ * was turned off by default unless the theme supported it. As a result, users
+ * suddenly were no longer able to access the settings they previously had access
+ * to. This turns the setting on for all wpcom users regardless of theme.
+ *
+ * @see https://github.com/WordPress/gutenberg/pull/23904
+ **/
+function jetpack_mu_wpcom_gutenberg_enable_custom_line_height() {
+	add_theme_support( 'custom-line-height' );
+}
+add_action( 'after_setup_theme', 'jetpack_mu_wpcom_gutenberg_enable_custom_line_height' );