Update from https://crrev.com/306655

net/cert/ct_log_response_parser.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/cert/ct_log_response_parser.h"
 
 #include "base/base64.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_value_converter.h"
 #include "base/logging.h"
@@ skipping 109 matching lines @@
     return false;
   }
 
   if (!IsJsonSTHStructurallyValid(parsed_sth))
     return false;
 
   signed_tree_head->version = SignedTreeHead::V1;
   signed_tree_head->tree_size = parsed_sth.tree_size;
   signed_tree_head->timestamp =
       base::Time::UnixEpoch() +
-      base::TimeDelta::FromMilliseconds(parsed_sth.timestamp);
+      base::TimeDelta::FromMilliseconds(
+          static_cast<int64>(parsed_sth.timestamp));
   signed_tree_head->signature = parsed_sth.signature;
   memcpy(signed_tree_head->sha256_root_hash,
          parsed_sth.sha256_root_hash.c_str(),
          kSthRootHashLength);
   return true;
 }
 
 }  // namespace ct
 
 }  // namespace net