Explicitly tell the preload request where to take the referrer from

third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/html/parser/PreloadRequest.h"
 
 #include "core/dom/Document.h"
 #include "core/loader/DocumentLoader.h"
 #include "platform/CrossOriginAttributeValue.h"
 #include "platform/loader/fetch/FetchInitiatorInfo.h"
@@ skipping 23 matching lines @@
   initiator_info.name = AtomicString(initiator_name_);
   initiator_info.position = initiator_position_;
 
   const KURL& url = CompleteURL(document);
   // Data URLs are filtered out in the preload scanner.
   DCHECK(!url.ProtocolIsData());
 
   ResourceRequest resource_request(url);
   resource_request.SetHTTPReferrer(SecurityPolicy::GenerateReferrer(
       referrer_policy_, url,
-      resource_type_ == Resource::kCSSStyleSheet
+      referrer_source_ == kBaseUrlIsReferrer
           ? base_url_.StrippedForUseAsReferrer()
           : document->OutgoingReferrer()));
   resource_request.SetRequestContext(
       ResourceFetcher::DetermineRequestContext(resource_type_, false));
 
   FetchRequest request(resource_request, initiator_info);
 
   if (resource_type_ == Resource::kImportResource) {
     SecurityOrigin* security_origin =
         document->ContextDocument()->GetSecurityOrigin();
@@ skipping 21 matching lines @@
       resource_type_ == Resource::kImportResource) {
     request.SetCharset(charset_.IsEmpty() ? document->characterSet().GetString()
                                           : charset_);
   }
   request.SetSpeculativePreload(true, discovery_time_);
 
   return document->Loader()->StartPreload(resource_type_, request);
 }
 
 }  // namespace blink