Upgrade: Add 'Upgraded' header, update 'Prefer' value.

Source/core/loader/FrameFetchContext.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 609 matching lines @@
 void FrameFetchContext::upgradeInsecureRequest(FetchRequest& fetchRequest)
 {
     if (!m_document || !RuntimeEnabledFeatures::experimentalContentSecurityPolicyFeaturesEnabled())
         return;
 
     KURL url = fetchRequest.resourceRequest().url();
 
     // Tack a 'Prefer' header to outgoing navigational requests, as described in
     // https://w3c.github.io/webappsec/specs/upgrade/#feature-detect
     if (fetchRequest.resourceRequest().frameType() != WebURLRequest::FrameTypeNone && !SecurityOrigin::isSecure(url))
-        fetchRequest.mutableResourceRequest().addHTTPHeaderField("Prefer", "return=secure-representation");
+        fetchRequest.mutableResourceRequest().addHTTPHeaderField("Prefer", "tls");
 
     if (m_document->insecureRequestsPolicy() == SecurityContext::InsecureRequestsUpgrade && url.protocolIs("http")) {
         // We always upgrade subresource requests and nested frames, we always upgrade form
         // submissions, and we always upgrade requests whose host matches the host of the
         // containing document's security origin.
         //
         // FIXME: We need to check the document that set the policy, not the current document.
         const ResourceRequest& request = fetchRequest.resourceRequest();
         if (request.frameType() == WebURLRequest::FrameTypeNone
             || request.frameType() == WebURLRequest::FrameTypeNested
             || request.requestContext() == WebURLRequest::RequestContextForm
             || url.host() == document()->securityOrigin()->host())
         {
             url.setProtocol("https");
             if (url.port() == 80)
                 url.setPort(443);
             fetchRequest.mutableResourceRequest().setURL(url);
+            fetchRequest.mutableResourceRequest().addHTTPHeaderField("Upgraded", "1");
         }
     }
 }
 
 void FrameFetchContext::addClientHintsIfNecessary(FetchRequest& fetchRequest)
 {
     if (!frame() || !RuntimeEnabledFeatures::clientHintsEnabled() || !m_document)
         return;
 
     if (frame()->shouldSendDPRHint())
         fetchRequest.mutableResourceRequest().addHTTPHeaderField("DPR", AtomicString(String::number(m_document->devicePixelRatio())));
 
     // FIXME: Send the RW hint based on the actual resource width, when we have it.
     if (frame()->shouldSendRWHint() && frame()->view())
         fetchRequest.mutableResourceRequest().addHTTPHeaderField("RW", AtomicString(String::number(frame()->view()->viewportWidth())));
 }
 
 DEFINE_TRACE(FrameFetchContext)
 {
     visitor->trace(m_document);
     FetchContext::trace(visitor);
 }
 
 } // namespace blink