Experiment with HSTS preload list filtering.

net/tools/transport_security_state_generator/pinsets.h

Index: net/tools/transport_security_state_generator/pinsets.h
diff --git a/net/tools/transport_security_state_generator/pinsets.h b/net/tools/transport_security_state_generator/pinsets.h
index 76790307db4e2660901ba86c0d494b412ee432a3..1eec3e30711531bda6a131a9b3b88d8749c4ecf3 100644
--- a/net/tools/transport_security_state_generator/pinsets.h
+++ b/net/tools/transport_security_state_generator/pinsets.h
@@ -7,6 +7,7 @@
 
 #include <map>
 #include <memory>
+#include <set>
 #include <string>
 
 #include "base/macros.h"
@@ -32,6 +33,10 @@ class Pinsets {
   void RegisterSPKIHash(base::StringPiece name, const SPKIHash& hash);
   void RegisterPinset(std::unique_ptr<Pinset> set);
 
+  // Removes all Pinsets whose name is not in |except_these|. Also removes the
+  // SPKI Hashes that are no longer referenced by the remaining pinsets.
+  void FilterPinsets(const std::set<std::string>& except_these);
+
   size_t size() const { return pinsets_.size(); }
   size_t spki_size() const { return spki_hashes_.size(); }