Implement referred Token Bindings

net/http/http_request_info.h

Index: net/http/http_request_info.h
diff --git a/net/http/http_request_info.h b/net/http/http_request_info.h
index 2079f193fd38d1a086934f31aedf181c5beb4abd..ceca265be3ba04edefbb37a921b07ffb50ff993d 100644
--- a/net/http/http_request_info.h
+++ b/net/http/http_request_info.h
@@ -52,6 +52,10 @@ struct NET_EXPORT HttpRequestInfo {
   // If enabled, then request must be sent over connection that cannot be
   // tracked by the server (e.g. without channel id).
   PrivacyMode privacy_mode;
+
+  // If present, the host of the referrer whose TokenBindingID should be
+  // included in a referred TokenBinding.
+  std::string token_binding_referrer;
 };
 
 }  // namespace net