Add a key purpose parameter to Certificate 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 108 matching lines @@
                          &intermediate_der_certs)) {
     std::cerr << "ERROR: Couldn't read certificate chain\n";
     return 1;
   }
 
   if (target_der_cert.der_cert.empty()) {
     std::cerr << "ERROR: no target cert\n";
     return 1;
   }
 
+  // TODO(eroman): Also use CertVerifyProcBuiltin.
+
   std::cout << "CertVerifyProc:\n";
   bool cert_verify_proc_ok = true;
   if (!time_flag.empty()) {
     std::cerr << "ERROR: --time is not supported with CertVerifyProc, "
                  "skipping.\n";
   } else if (hostname.empty()) {
     std::cerr << "ERROR: --hostname is required for CertVerifyProc, skipping\n";
   } else {
     cert_verify_proc_ok = VerifyUsingCertVerifyProc(
         target_der_cert, hostname, intermediate_der_certs, root_der_certs,
         dump_prefix_path);
   }
 
   std::cout << "\nCertPathBuilder:\n";
 
   if (!hostname.empty()) {
     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;
 }