LibWeb: Start adding infrastructure for an HTTP Cache

Author: https://github.com/ADKaster
Commit: c05f296014
Pull-request: https://github.com/SerenityOS/serenity/pull/24406
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/trflynn89 ✅

Userland/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h

@@ -33,7 +33,7 @@ struct Header {
 // A header list is a list of zero or more headers. It is initially the empty list.
 class HeaderList final
     : public JS::Cell
-    , Vector<Header> {
+    , public Vector<Header> {
     JS_CELL(HeaderList, JS::Cell);
     JS_DECLARE_ALLOCATOR(HeaderList);