MD Settings: Prevent direct navigation to disabled Site Settings UI.

chrome/browser/resources/settings/route.js

Index: chrome/browser/resources/settings/route.js
diff --git a/chrome/browser/resources/settings/route.js b/chrome/browser/resources/settings/route.js
index 87a714c04bcf503f13159446ab22f008ea7f161a..7d02247ac41f455d75716f19944950db897666bd 100644
--- a/chrome/browser/resources/settings/route.js
+++ b/chrome/browser/resources/settings/route.js
@@ -148,9 +148,12 @@ cr.define('settings', function() {
   r.CERTIFICATES = r.PRIVACY.createChild('/certificates');
 
   r.SITE_SETTINGS = r.PRIVACY.createChild('/content');
-  r.SITE_SETTINGS_ALL = r.SITE_SETTINGS.createChild('all');
-  r.SITE_SETTINGS_SITE_DETAILS =
-      r.SITE_SETTINGS_ALL.createChild('/content/siteDetails');
+
+  if (loadTimeData.getBoolean('enableSiteSettings')) {
+    r.SITE_SETTINGS_ALL = r.SITE_SETTINGS.createChild('all');
+    r.SITE_SETTINGS_SITE_DETAILS =
+        r.SITE_SETTINGS_ALL.createChild('/content/siteDetails');
+  }
 
   r.SITE_SETTINGS_HANDLERS = r.SITE_SETTINGS.createChild('/handlers');