Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/masterminds/html5/src/HTML5/Parser/ParseError.php

@@ -0,0 +1,9 @@
+<?php
+namespace Masterminds\HTML5\Parser;
+
+/**
+ * Emit when the parser has an error.
+ */
+class ParseError extends \Exception
+{
+}