Use Referrer-Policy headers for CSS stylesheets

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

Index: third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp b/third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp
index d1694840a858ca62db070766c915320018d1a0c6..5c83e5328cffbb73461ac5daceeb3c2a6a1fce04 100644
--- a/third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp
+++ b/third_party/WebKit/Source/core/html/parser/PreloadRequest.cpp
@@ -40,7 +40,10 @@ Resource* PreloadRequest::start(Document* document) {
 
   ResourceRequest resourceRequest(url);
   resourceRequest.setHTTPReferrer(SecurityPolicy::generateReferrer(
-      m_referrerPolicy, url, document->outgoingReferrer()));
+      m_referrerPolicy, url,
+      m_resourceType == Resource::CSSStyleSheet
+          ? m_baseURL.strippedForUseAsReferrer()
+          : document->outgoingReferrer()));
   resourceRequest.setRequestContext(
       ResourceFetcher::determineRequestContext(m_resourceType, false));