cache lastwebprefs

lib/browser/guest-view-manager.js

@@ -250,8 +250,9 @@ const attachGuest = function (event, elementInstanceId, guestInstanceId, params)
   ])
 
   // Inherit certain option values from embedder
+  const lastWebPreferences = embedder.getLastWebPreferences()
   for (const [name, value] of inheritedWebPreferences) {
-    if (embedder.getLastWebPreferences()[name] === value) {
+    if (lastWebPreferences[name] === value) {
       webPreferences[name] = value
     }
   }