diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index 882c9e91..b33f3e40 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -741,8 +741,10 @@ void URLRequestHttpJob::SaveCookiesAndNotifyHeadersComplete(int result) {
           request_->url(), request_->site_for_cookies())) {
     force_ignore_site_for_cookies = true;
   }
-  bool is_main_frame_navigation = IsolationInfo::RequestType::kMainFrame ==
-                                  request_->isolation_info().request_type();
+  bool is_main_frame_navigation =
+      IsolationInfo::RequestType::kMainFrame ==
+          request_->isolation_info().request_type() ||
+      request_->force_main_frame_for_same_site_cookies();
   CookieOptions::SameSiteCookieContext same_site_context =
       net::cookie_util::ComputeSameSiteContextForResponse(
           request_->url_chain(), request_->site_for_cookies(),