Editor: Add custom fields meta box support in the block editor.

This brings support for the custom fields meta box into the new block editor.

The `webpack` and `copy-webpack-plugin` packages have also been updated.

This does not bump the `@wordpress` packages like in [43861] because of conflicts with package versions already installed in `trunk`. The packages will be brought up to date in a subsequent merge.

Merges [43861] and [43863] into trunk.

See #45145.
Fixes #45257.
Built from https://develop.svn.wordpress.org/trunk@44260


git-svn-id: http://core.svn.wordpress.org/trunk@44090 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/edit-form-blocks.php

@@ -202,6 +202,29 @@ if ( $editor_styles && current_theme_supports( 'editor-styles' ) ) {
 	}
 }
 
+// Image sizes.
+$image_sizes   = get_intermediate_image_sizes();
+$image_sizes[] = 'full';
+
+/** This filter is documented in wp-admin/includes/media.php */
+$image_size_names = apply_filters(
+	'image_size_names_choose',
+	array(
+		'thumbnail' => __( 'Thumbnail' ),
+		'medium'    => __( 'Medium' ),
+		'large'     => __( 'Large' ),
+		'full'      => __( 'Full Size' ),
+	)
+);
+
+$available_image_sizes = array();
+foreach ( $image_sizes as $image_size_slug ) {
+	$available_image_sizes[] = array(
+		'slug' => $image_size_slug,
+		'name' => isset( $image_size_names[ $image_size_slug ] ) ? $image_size_names[ $image_size_slug ] : $image_size_slug,
+	);
+}
+
 // Lock settings.
 $user_id = wp_check_post_lock( $post->ID );
 if ( $user_id ) {
@@ -257,12 +280,17 @@ $editor_settings = array(
 	'maxUploadFileSize'      => $max_upload_size,
 	'allowedMimeTypes'       => get_allowed_mime_types(),
 	'styles'                 => $styles,
+	'availableImageSizes'    => $available_image_sizes,
 	'postLock'               => $lock_details,
 	'postLockUtils'          => array(
 		'nonce'       => wp_create_nonce( 'lock-post_' . $post->ID ),
 		'unlockNonce' => wp_create_nonce( 'update-post_' . $post->ID ),
 		'ajaxUrl'     => admin_url( 'admin-ajax.php' ),
 	),
+
+	// Whether or not to load the 'postcustom' meta box is stored as a user meta
+	// field so that we're not always loading its assets.
+	'enableCustomFields'     => (bool) get_user_meta( get_current_user_id(), 'enable_custom_fields', true ),
 );
 
 $autosave = wp_get_post_autosave( $post_ID );