Reload cache control: remove redundant header insertion from Blink

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 556 matching lines @@
     ASSERT(memoryCache()->contains(resource));
     ASSERT(resource->isLoaded());
     ASSERT(resource->canUseCacheValidator());
     ASSERT(!resource->isCacheValidator());
     ASSERT(!context().isControlledByServiceWorker());
 
     ResourceRequest revalidatingRequest(resource->resourceRequest());
     revalidatingRequest.clearHTTPReferrer();
     initializeResourceRequest(revalidatingRequest, resource->getType(), request.defer());
 
-    const AtomicString& lastModified = resource->response().httpHeaderField(HTTPNames::Last_Modified);
-    const AtomicString& eTag = resource->response().httpHeaderField(HTTPNames::ETag);
-    if (!lastModified.isEmpty() || !eTag.isEmpty()) {
-        ASSERT(context().getCachePolicy() != CachePolicyReload);
-        if (context().getCachePolicy() == CachePolicyRevalidate)
-            revalidatingRequest.setHTTPHeaderField(HTTPNames::Cache_Control, "max-age=0");
-    }
-    if (!lastModified.isEmpty())
-        revalidatingRequest.setHTTPHeaderField(HTTPNames::If_Modified_Since, lastModified);
-    if (!eTag.isEmpty())
-        revalidatingRequest.setHTTPHeaderField(HTTPNames::If_None_Match, eTag);
-
+    // TODO(toyoshim): Figure out if following code is really needed and
+    // how this code works with Stale-While-Revalidate field trial.
     double stalenessLifetime = resource->stalenessLifetime();
     if (std::isfinite(stalenessLifetime) && stalenessLifetime > 0) {
         revalidatingRequest.setHTTPHeaderField(HTTPNames::Resource_Freshness, AtomicString(String::format("max-age=%.0lf,stale-while-revalidate=%.0lf,age=%.0lf", resource->freshnessLifetime(), stalenessLifetime, resource->currentAge())));
     }
 
     resource->setRevalidatingRequest(revalidatingRequest);
 }
 
 Resource* ResourceFetcher::createResourceForLoading(FetchRequest& request, const String& charset, const ResourceFactory& factory)
 {
@@ skipping 660 matching lines @@
     visitor->trace(m_context);
     visitor->trace(m_archive);
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
     visitor->trace(m_documentResources);
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 }
 
 } // namespace blink