diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-admin/includes/class-wp-site-icon.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-admin/includes/class-wp-site-icon.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,233 @@
+<?php
+/**
+ * Administration API: WP_Site_Icon class
+ *
+ * @package WordPress
+ * @subpackage Administration
+ * @since 4.3.0
+ */
+
+/**
+ * Core class used to implement site icon functionality.
+ *
+ * @since 4.3.0
+ */
+class WP_Site_Icon {
+
+	/**
+	 * The minimum size of the site icon.
+	 *
+	 * @since 4.3.0
+	 * @var int
+	 */
+	public $min_size  = 512;
+
+	/**
+	 * The size to which to crop the image so that we can display it in the UI nicely.
+	 *
+	 * @since 4.3.0
+	 * @var int
+	 */
+	public $page_crop = 512;
+
+	/**
+	 * List of site icon sizes.
+	 *
+	 * @since 4.3.0
+	 * @var array
+	 */
+	public $site_icon_sizes = array(
+		/*
+		 * Square, medium sized tiles for IE11+.
+		 *
+		 * See https://msdn.microsoft.com/library/dn455106(v=vs.85).aspx
+		 */
+		270,
+
+		/*
+		 * App icon for Android/Chrome.
+		 *
+		 * @link https://developers.google.com/web/updates/2014/11/Support-for-theme-color-in-Chrome-39-for-Android
+		 * @link https://developer.chrome.com/multidevice/android/installtohomescreen
+		 */
+		192,
+
+		/*
+		 * App icons up to iPhone 6 Plus.
+		 *
+		 * See https://developer.apple.com/library/prerelease/ios/documentation/UserExperience/Conceptual/MobileHIG/IconMatrix.html
+		 */
+		180,
+
+		// Our regular Favicon.
+		32,
+	);
+
+	/**
+	 * Registers actions and filters.
+	 *
+	 * @since 4.3.0
+	 */
+	public function __construct() {
+		add_action( 'delete_attachment', array( $this, 'delete_attachment_data' ) );
+		add_filter( 'get_post_metadata', array( $this, 'get_post_metadata' ), 10, 4 );
+	}
+
+	/**
+	 * Creates an attachment 'object'.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param string $cropped              Cropped image URL.
+	 * @param int    $parent_attachment_id Attachment ID of parent image.
+	 * @return array Attachment object.
+	 */
+	public function create_attachment_object( $cropped, $parent_attachment_id ) {
+		$parent     = get_post( $parent_attachment_id );
+		$parent_url = wp_get_attachment_url( $parent->ID );
+		$url        = str_replace( basename( $parent_url ), basename( $cropped ), $parent_url );
+
+		$size       = @getimagesize( $cropped );
+		$image_type = ( $size ) ? $size['mime'] : 'image/jpeg';
+
+		$object = array(
+			'ID'             => $parent_attachment_id,
+			'post_title'     => basename( $cropped ),
+			'post_content'   => $url,
+			'post_mime_type' => $image_type,
+			'guid'           => $url,
+			'context'        => 'site-icon'
+		);
+
+		return $object;
+	}
+
+	/**
+	 * Inserts an attachment.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param array  $object Attachment object.
+	 * @param string $file   File path of the attached image.
+	 * @return int           Attachment ID
+	 */
+	public function insert_attachment( $object, $file ) {
+		$attachment_id = wp_insert_attachment( $object, $file );
+		$metadata      = wp_generate_attachment_metadata( $attachment_id, $file );
+
+		/**
+		 * Filters the site icon attachment metadata.
+		 *
+		 * @since 4.3.0
+		 *
+		 * @see wp_generate_attachment_metadata()
+		 *
+		 * @param array $metadata Attachment metadata.
+		 */
+		$metadata = apply_filters( 'site_icon_attachment_metadata', $metadata );
+		wp_update_attachment_metadata( $attachment_id, $metadata );
+
+		return $attachment_id;
+	}
+
+	/**
+	 * Adds additional sizes to be made when creating the site_icon images.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param array $sizes List of additional sizes.
+	 * @return array Additional image sizes.
+	 */
+	public function additional_sizes( $sizes = array() ) {
+		$only_crop_sizes = array();
+
+		/**
+		 * Filters the different dimensions that a site icon is saved in.
+		 *
+		 * @since 4.3.0
+		 *
+		 * @param array $site_icon_sizes Sizes available for the Site Icon.
+		 */
+		$this->site_icon_sizes = apply_filters( 'site_icon_image_sizes', $this->site_icon_sizes );
+
+		// Use a natural sort of numbers.
+		natsort( $this->site_icon_sizes );
+		$this->site_icon_sizes = array_reverse( $this->site_icon_sizes );
+
+		// ensure that we only resize the image into
+		foreach ( $sizes as $name => $size_array ) {
+			if ( isset( $size_array['crop'] ) ) {
+				$only_crop_sizes[ $name ] = $size_array;
+			}
+		}
+
+		foreach ( $this->site_icon_sizes as $size ) {
+			if ( $size < $this->min_size ) {
+				$only_crop_sizes[ 'site_icon-' . $size ] = array(
+					'width ' => $size,
+					'height' => $size,
+					'crop'   => true,
+				);
+			}
+		}
+
+		return $only_crop_sizes;
+	}
+
+	/**
+	 * Adds Site Icon sizes to the array of image sizes on demand.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param array $sizes List of image sizes.
+	 * @return array List of intermediate image sizes.
+	 */
+	public function intermediate_image_sizes( $sizes = array() ) {
+		/** This filter is documented in wp-admin/includes/class-wp-site-icon.php */
+		$this->site_icon_sizes = apply_filters( 'site_icon_image_sizes', $this->site_icon_sizes );
+		foreach ( $this->site_icon_sizes as $size ) {
+			$sizes[] = 'site_icon-' . $size;
+		}
+
+		return $sizes;
+	}
+
+	/**
+	 * Deletes the Site Icon when the image file is deleted.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param int $post_id Attachment ID.
+	 */
+	public function delete_attachment_data( $post_id ) {
+		$site_icon_id = get_option( 'site_icon' );
+
+		if ( $site_icon_id && $post_id == $site_icon_id ) {
+			delete_option( 'site_icon' );
+		}
+	}
+
+	/**
+	 * Adds custom image sizes when meta data for an image is requested, that happens to be used as Site Icon.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param null|array|string $value    The value get_metadata() should return a single metadata value, or an
+	 *                                    array of values.
+	 * @param int               $post_id  Post ID.
+	 * @param string            $meta_key Meta key.
+	 * @param string|array      $single   Meta value, or an array of values.
+	 * @return array|null|string The attachment metadata value, array of values, or null.
+	 */
+	public function get_post_metadata( $value, $post_id, $meta_key, $single ) {
+		if ( $single && '_wp_attachment_backup_sizes' === $meta_key ) {
+			$site_icon_id = get_option( 'site_icon' );
+
+			if ( $post_id == $site_icon_id ) {
+				add_filter( 'intermediate_image_sizes', array( $this, 'intermediate_image_sizes' ) );
+			}
+		}
+
+		return $value;
+	}
+}