TinyMCE: improve removal of spaces from empty paragraphs when loading HTML in the editor.

Fixes #39437.
Built from https://develop.svn.wordpress.org/trunk@39902


git-svn-id: http://core.svn.wordpress.org/trunk@39839 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/tinymce/plugins/wordpress/plugin.js

@@ -129,19 +129,22 @@ tinymce.PluginManager.add( 'wordpress', function( editor ) {
 					'/>';
 				} );
 			}
-
-			// Remove spaces from empty paragraphs.
-			// Try to avoid a lot of backtracking, can freeze the editor. See #35890 and #38294.
-			event.content = event.content.replace( /<p>([^<>]+)<\/p>/gi, function( tag, text ) {
-				if ( text === '&nbsp;' || ! /\S/.test( text ) ) {
-					return '<p><br /></p>';
-				}
-
-				return tag;
-			});
 		}
 	});
 
+	editor.on( 'setcontent', function() {
+		// Remove spaces from empty paragraphs.
+		editor.$( 'p' ).each( function( i, node ) {
+			if ( node.innerHTML && node.innerHTML.length < 10 ) {
+				var html = tinymce.trim( node.innerHTML );
+
+				if ( ! html || html === '&nbsp;' ) {
+					node.innerHTML = ( tinymce.Env.ie && tinymce.Env.ie < 11 ) ? '' : '<br data-mce-bogus="1">';
+				}
+			}
+		} );
+	});
+
 	editor.on( 'PostProcess', function( event ) {
 		if ( event.get ) {
 			event.content = event.content.replace(/<img[^>]+>/g, function( image ) {

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39901';
+$wp_version = '4.8-alpha-39902';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.