Media: ensure JavaScript initialized when media edit screen is loaded directly.

Fix a JavaScript error when the media edit screen is loaded directly via a url such as `/wp-admin/post.php?post={post_id}&action=edit&image-editor`. Add a check in `imgLoaded` for `this.hold.sizer` which is set up during initialization and required for the cropping tool. Call `init` if this is undefined.

Props NoseGraze.
Fixes #38138.

Built from https://develop.svn.wordpress.org/trunk@40020


git-svn-id: http://core.svn.wordpress.org/trunk@39957 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/image-edit.js

@@ -573,6 +573,11 @@
 	imgLoaded : function(postid) {
 		var img = $('#image-preview-' + postid), parent = $('#imgedit-crop-' + postid);
 
+		// Ensure init has run even when directly loaded.
+		if ( 'undefined' === typeof this.hold.sizer ) {
+			this.init( postid );
+		}
+
 		this.initCrop(postid, img, parent);
 		this.setCropSelection(postid, 0);
 		this.toggleEditor(postid, 0);

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-40019';
+$wp_version = '4.8-alpha-40020';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.