Actually handle the Vary header in blink, rather than punting on sight.

third_party/WebKit/Source/platform/loader/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
@@ skipping 952 matching lines @@
     return Reload;
   }
 
   // List of available images logic allows images to be re-used without cache
   // validation. We restrict this only to images from memory cache which are the
   // same as the version in the current document.
   if (type == Resource::Image &&
       existingResource == cachedResource(request.url()))
     return Use;
 
-  // Defer to the browser process cache for Vary header handling.
-  if (existingResource->hasVaryHeader())
+  if (existingResource->mustReloadDueToVaryHeader(request))
     return Reload;
 
   // If any of the redirects in the chain to loading the resource were not
   // cacheable, we cannot reuse our cached resource.
   if (!existingResource->canReuseRedirectChain()) {
     RESOURCE_LOADING_DVLOG(1) << "ResourceFetcher::determineRevalidationPolicy "
                                  "reloading due to an uncacheable redirect";
     return Reload;
   }
 
@@ skipping 558 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