Certificate Transparency: Start tracking logs' state

net/cert/signed_tree_head.cc

Index: net/cert/signed_tree_head.cc
diff --git a/net/cert/signed_tree_head.cc b/net/cert/signed_tree_head.cc
index 8bf2b9f3ff7755fae4e6082f1f7528fbd166dafe..df6505d3edfa3ed4797d0477aaa06b0a2531b9d0 100644
--- a/net/cert/signed_tree_head.cc
+++ b/net/cert/signed_tree_head.cc
@@ -33,6 +33,14 @@ SignedTreeHead::SignedTreeHead(const SignedTreeHead& other) = default;
 
 SignedTreeHead::~SignedTreeHead() {}
 
+bool operator==(const SignedTreeHead& sth1, const SignedTreeHead& sth2) {
+  return sth1.log_id == sth2.log_id && sth1.timestamp == sth2.timestamp;
+}
+
+bool operator!=(const SignedTreeHead& sth1, const SignedTreeHead& sth2) {
+  return !(sth1 == sth2);
+}
+
 void PrintTo(const SignedTreeHead& sth, std::ostream* os) {
   (*os) << "{\n"
         << "\t\"version\": " << sth.version << ",\n"