Backport from Core: Reuse block metadata in WP_Theme_JSON::get_valid_…

…block_style_variations() for better performance (WordPress#66539)

* Backporting theme json performance optimizations from WordPress/wordpress-develop#7586

* Tentatively backport using `get_blocks_metadata` instead of `WP_Block_Type_Registry` to get block names.

Co-authored-by: ramonjd <[email protected]>
Co-authored-by: mukeshpanchal27 <[email protected]>
Co-authored-by: aaronrobertshaw <[email protected]>

lib/class-wp-theme-json-gutenberg.php

@@ -745,10 +745,10 @@ public function __construct( $theme_json = array( 'version' => WP_Theme_JSON_Gut
 		}
 
 		$this->theme_json    = WP_Theme_JSON_Schema_Gutenberg::migrate( $theme_json, $origin );
-		$registry            = WP_Block_Type_Registry::get_instance();
-		$valid_block_names   = array_keys( $registry->get_all_registered() );
+		$blocks_metadata     = static::get_blocks_metadata();
+		$valid_block_names   = array_keys( $blocks_metadata );
 		$valid_element_names = array_keys( static::ELEMENTS );
-		$valid_variations    = static::get_valid_block_style_variations();
+		$valid_variations    = static::get_valid_block_style_variations( $blocks_metadata );
 		$this->theme_json    = static::unwrap_shared_block_style_variations( $this->theme_json, $valid_variations );
 		$this->theme_json    = static::sanitize( $this->theme_json, $valid_block_names, $valid_element_names, $valid_variations );
 		$this->theme_json    = static::maybe_opt_in_into_settings( $this->theme_json );
@@ -3506,9 +3506,10 @@ public static function remove_insecure_properties( $theme_json, $origin = 'theme
 
 		$theme_json = WP_Theme_JSON_Schema_Gutenberg::migrate( $theme_json, $origin );
 
-		$valid_block_names   = array_keys( static::get_blocks_metadata() );
+		$blocks_metadata     = static::get_blocks_metadata();
+		$valid_block_names   = array_keys( $blocks_metadata );
 		$valid_element_names = array_keys( static::ELEMENTS );
-		$valid_variations    = static::get_valid_block_style_variations();
+		$valid_variations    = static::get_valid_block_style_variations( $blocks_metadata );
 
 		$theme_json = static::sanitize( $theme_json, $valid_block_names, $valid_element_names, $valid_variations );
 
@@ -4511,11 +4512,16 @@ function ( $matches ) use ( $variation_class ) {
 	/**
 	 * Collects valid block style variations keyed by block type.
 	 *
+	 * @since 6.6.0
+	 * @since 6.8.0 Added the `$blocks_metadata` parameter.
+	 *
+	 * @param array $blocks_metadata Optional. List of metadata per block. Default is the metadata for all blocks.
 	 * @return array Valid block style variations by block type.
 	 */
-	protected static function get_valid_block_style_variations() {
+	protected static function get_valid_block_style_variations( $blocks_metadata = array() ) {
 		$valid_variations = array();
-		foreach ( self::get_blocks_metadata() as $block_name => $block_meta ) {
+		$blocks_metadata  = empty( $blocks_metadata ) ? static::get_blocks_metadata() : $blocks_metadata;
+		foreach ( $blocks_metadata as $block_name => $block_meta ) {
 			if ( ! isset( $block_meta['styleVariations'] ) ) {
 				continue;
 			}