LibWeb/Fetch: Add a constant for the keepalive maximum size

Author: https://github.com/jamierocks
Commit: 35047de1d8
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1025
Reviewed-by: https://github.com/tcl3 ✅

Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp

@@ -1670,7 +1670,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<PendingResponse>> http_network_or_cache_fet
             }
 
             // 5. If the sum of contentLength and inflightKeepaliveBytes is greater than 64 kibibytes, then return a network error.
-            if ((content_length.value() + inflight_keep_alive_bytes) > 65536)
+            if ((content_length.value() + inflight_keep_alive_bytes) > keepalive_maximum_size)
                 return PendingResponse::create(vm, request, Infrastructure::Response::network_error(vm, "Keepalive request exceeded maximum allowed size of 64 KiB"sv));
 
             // NOTE: The above limit ensures that requests that are allowed to outlive the environment settings object