Index: wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js
===================================================================
--- wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js	(revision 23144)
+++ wp-includes/js/tinymce/plugins/wordpress/editor_plugin_src.js	(working copy)
@@ -135,12 +135,6 @@
 				}
 			});
 
-			// Extend <object> and <embed> (#WP22790)
-			ed.onPreInit.add(function(ed) {
-				ed.schema.addValidElements('object[*],param[id|name|value|valuetype|type],embed[*]');
-				ed.schema.addValidChildren('+object[embed]');
-			});
-
 			ed.onInit.add(function(ed) {
 				var bodyClass = ed.getParam('body_class', ''), body = ed.getBody();
 
Index: wp-includes/class-wp-editor.php
===================================================================
--- wp-includes/class-wp-editor.php	(revision 23144)
+++ wp-includes/class-wp-editor.php	(working copy)
@@ -345,7 +345,8 @@
 					'paste_text_use_dialog' => true,
 					'webkit_fake_resize' => false,
 					'spellchecker_rpc_url' => self::$baseurl . '/plugins/spellchecker/rpc.php',
-					'schema' => 'html5',
+					'schema' => 'html4',
+					'extended_valid_elements' => 'article[*],aside[*],audio[*],canvas[*],command[*],datalist[*],details[*],embed[*],figcaption[*],figure[*],footer[*],header[*],hgroup[*],keygen[*],mark[*],meter[*],nav[*],output[*],progress[*],section[*],source[*],summary,time[*],video[*],wbr',
 					'wpeditimage_disable_captions' => $no_captions,
 					'wp_fullscreen_content_css' => self::$baseurl . '/plugins/wpfullscreen/css/wp-fullscreen.css',
 					'plugins' => implode( ',', $plugins )