Send net's ReferrerPolicy back to Blink while following redirects

net/url_request/url_request.h

Index: net/url_request/url_request.h
diff --git a/net/url_request/url_request.h b/net/url_request/url_request.h
index 6992fb87ab8b8f7c2411178c72e86aafde88c72f..da5d9d8ea97d388fd6cf058f575bb28bcef33a02 100644
--- a/net/url_request/url_request.h
+++ b/net/url_request/url_request.h
@@ -83,7 +83,11 @@ class NET_EXPORT URLRequest : NON_EXPORTED_BASE(public base::NonThreadSafe),
 
   // A ReferrerPolicy for the request can be set with
   // set_referrer_policy() and controls the contents of the Referer
-  // header when URLRequest follows server redirects.
+  // header when URLRequest follows server redirects. Note that setting
+  // a ReferrerPolicy on the request has no effect on the Referer header
+  // of the initial leg of the request; the caller is responsible for
+  // setting the initial Referer, and the ReferrerPolicy only controls
+  // what happens to the Referer while following redirects.
   enum ReferrerPolicy {
     // Clear the referrer header if the protocol changes from HTTPS to
     // HTTP. This is the default behavior of URLRequest.