Introduce X-XSS-Protection header

Change-Id: I1b85d04743361343a09ca6d32593720a991a9e9f
diff --git a/t/page.t b/t/page.t
index c9bce7f..9146c0f 100644
--- a/t/page.t
+++ b/t/page.t
@@ -34,6 +34,7 @@
   ->header_is('X-Content-Type-Options', 'nosniff')
   ->header_is('Access-Control-Allow-Methods','GET, POST, OPTIONS')
   ->header_is('X-Frame-Options', 'sameorigin')
+  ->header_is('X-XSS-Protection', '1; mode=block')
   ;
 
 # Test additions