Remove dependence on a message loop for net::PathBuilder.

net/tools/cert_verify_tool/cert_verify_tool.cc

 // Copyright 2016 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 <iostream>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 51 matching lines @@
   // TODO(mattm): allow <certs path> to be a directory containing DER/PEM files?
   // TODO(mattm): allow target to specify an HTTPS URL to check the cert of?
   // TODO(mattm): allow target to be a verify_certificate_chain_unittest PEM
   // file?
 }
 
 }  // namespace
 
 int main(int argc, char** argv) {
   base::AtExitManager at_exit_manager;
+  // TODO(eroman): Is this needed?
   base::MessageLoopForIO message_loop;
   if (!base::CommandLine::Init(argc, argv)) {
     std::cerr << "ERROR in CommandLine::Init\n";
     return 1;
   }
   base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
   logging::LoggingSettings settings;
   settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;
   logging::InitLogging(settings);
 
@@ skipping 62 matching lines @@
     std::cerr
         << "WARNING: --hostname is not yet verified with CertPathBuilder\n";
   }
 
   bool path_builder_ok =
       VerifyUsingPathBuilder(target_der_cert, intermediate_der_certs,
                              root_der_certs, verify_time, dump_prefix_path);
 
   return (cert_verify_proc_ok && path_builder_ok) ? 0 : 1;
 }