net: limit HSTS ages to one year.

net/base/transport_security_state.h

Index: net/base/transport_security_state.h
diff --git a/net/base/transport_security_state.h b/net/base/transport_security_state.h
index 49b44d7350655dfc01c824e8a6e12d1738a029bf..fcd4e79a33a09ca315368160be7f77493de58a28 100644
--- a/net/base/transport_security_state.h
+++ b/net/base/transport_security_state.h
@@ -88,6 +88,9 @@ class TransportSecurityState :
   bool Serialise(std::string* output);
   bool Deserialise(const std::string& state, bool* dirty);
 
+  // The maximum number of seconds for which we'll cache an HSTS request.
+  static const long int kMaxHSTSAgeSecs;
+
  private:
   friend class base::RefCountedThreadSafe<TransportSecurityState>;
   FRIEND_TEST_ALL_PREFIXES(TransportSecurityStateTest, IsPreloaded);