Make it easier and more efficient to use trusted HTML text

tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart

Index: tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart
diff --git a/tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart b/tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart
index a2a23c6823e390c738df00ea26a971f5c6e791f9..dfdcbdbddee8890641aa0a3e49e61043111d95c5 100644
--- a/tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart
+++ b/tests/html/node_validator_important_if_you_suppress_make_the_bug_critical_test.dart
@@ -14,13 +14,10 @@ import 'package:unittest/unittest.dart';
 import 'package:unittest/html_individual_config.dart';
 import 'utils.dart';
 
-
-var nullSanitizer = new NullTreeSanitizer();
-
 void validateHtml(String html, String reference, NodeValidator validator) {
   var a = document.body.createFragment(html, validator: validator);
   var b = document.body.createFragment(reference,
-      treeSanitizer: nullSanitizer);
+      treeSanitizer: NodeTreeSanitizer.trusted);
 
   // Prevent a false pass when both the html and the reference both get entirely
   // deleted, which is technically a match, but unlikely to be what we meant.