Add an SignedCertificateTimetampStore, making SignedCertificateTimestamp be refcounted to aid.

net/cert/signed_certificate_timestamp.cc

Index: net/cert/signed_certificate_timestamp.cc
diff --git a/net/cert/signed_certificate_timestamp.cc b/net/cert/signed_certificate_timestamp.cc
index 0be511d41dbb64cde0fe151d0ee41f40e664eb3d..7fed9ae2cb9b18bc80aa9180c3f301c0d20bc251 100644
--- a/net/cert/signed_certificate_timestamp.cc
+++ b/net/cert/signed_certificate_timestamp.cc
@@ -8,6 +8,15 @@ namespace net {
 
 namespace ct {
 
+bool SignedCertificateTimestamp::LessThan::operator()(
+    const scoped_refptr<SignedCertificateTimestamp>& lhs,
+    const scoped_refptr<SignedCertificateTimestamp>& rhs) const {
+  if (lhs.get() == rhs.get())
+    return false;
+
+  return lhs->signature.signature_data < rhs->signature.signature_data;
+}
+
 SignedCertificateTimestamp::SignedCertificateTimestamp() {}
 
 SignedCertificateTimestamp::~SignedCertificateTimestamp() {}