Issue 984 - port referrer mapping from Android

include/AdblockPlus/ReferrerMapping.h

Index: include/AdblockPlus/ReferrerMapping.h
===================================================================
new file mode 100644
--- /dev/null
+++ b/include/AdblockPlus/ReferrerMapping.h
@@ -0,0 +1,42 @@
+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2014 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef ADBLOCK_PLUS_REFERRER_MAPPING_H
+#define ADBLOCK_PLUS_REFERRER_MAPPING_H
+
+#include <list>
+#include <map>
+#include <string>
+#include <vector>
+
+namespace AdblockPlus
+{
+  class ReferrerMapping
+  {
+  public:
+    ReferrerMapping(const int maxCachedUrls = 5000);
+    void Add(const std::string& url, const std::string& referrer);
+    std::vector<std::string> BuildReferrerChain(const std::string& url) const;
+
+  private:
+    const int maxCachedUrls;
+    std::map<std::string, std::string> mapping;
+    std::list<std::string> cachedUrls;
+  };
+}
+
+#endif