Index: src/ReferrerMapping.cpp
diff --git a/src/ReferrerMapping.cpp b/src/ReferrerMapping.cpp
index 7ac6cddff5bf2452670c6d2b986f0802fb5de4d2..0dae687e90bbd7af59ce89c117f6294411e0c937 100644
--- a/src/ReferrerMapping.cpp
+++ b/src/ReferrerMapping.cpp
@@ -24,12 +24,12 @@ ReferrerMapping::ReferrerMapping(const int maxCachedUrls)
 {
 }
 
-void ReferrerMapping::Add(const std::string& url, const std::string& referrer)
+void ReferrerMapping::Add(const Url& url, const Url& referrer, FrameIndicator isFrame)
 {
   if (mapping.find(url) != mapping.end())
     cachedUrls.remove(url);
   cachedUrls.push_back(url);
-  mapping[url] = referrer;
+  mapping[url] = RequestInfo(referrer, isFrame);
 
   const int urlsToPop = cachedUrls.size() - maxCachedUrls;
   for (int i = 0; i < urlsToPop; i++)
@@ -40,21 +40,35 @@ void ReferrerMapping::Add(const std::string& url, const std::string& referrer)
   }
 }
 
-std::vector<std::string> ReferrerMapping::BuildReferrerChain(
-  const std::string& url) const
+ReferrerMapping::Urls ReferrerMapping::BuildFrameStructure(const Url& url) const
 {
-  std::vector<std::string> referrerChain;
-  referrerChain.push_back(url);
+  Urls frames;
   // We need to limit the chain length to ensure we don't block indefinitely
   // if there's a referrer loop.
   const int maxChainLength = 10;
-  std::map<std::string, std::string>::const_iterator currentEntry =
+  ReferrerMap::const_iterator currentEntry = url.empty() ? mapping.end() :
     mapping.find(url);
+  ReferrerMap::const_iterator prevEntry = mapping.end();
   for (int i = 0; i < maxChainLength && currentEntry != mapping.end(); i++)
   {
-    const std::string& currentUrl = currentEntry->second;
-    referrerChain.insert(referrerChain.begin(), currentUrl);
-    currentEntry = mapping.find(currentUrl);
+    if (currentEntry->second.IsFrame())
+    {
+      frames.insert(frames.begin(), currentEntry->first);
+    }
+    prevEntry = currentEntry;
+    currentEntry = mapping.find(currentEntry->second.referrer);
   }
-  return referrerChain;
+  if (prevEntry == mapping.end())
+  {
+    if (!url.empty())
+    {
+      // No data, just assume that the url is a frame.
+      frames.push_back(url);
+    }
+  }
+  else if (!prevEntry->second.referrer.empty())
+  {
+    frames.insert(frames.begin(), prevEntry->second.referrer);
+  }
+  return frames;
 }