certificate manager: Disable export option for TPM-backed certs.

chrome/browser/certificate_manager_model.cc

 // Copyright (c) 2011 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 "chrome/browser/certificate_manager_model.h"
 
 #include "base/bind.h"
 #include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/utf_string_conversions.h"
@@ skipping 63 matching lines @@
     const net::X509Certificate& cert,
     Column column) const {
   string16 rv;
   switch (column) {
     case COL_SUBJECT_NAME:
       rv = UTF8ToUTF16(
           x509_certificate_model::GetCertNameOrNickname(cert.os_cert_handle()));
 
 #if defined(OS_CHROMEOS)
       // TODO(xiyuan): Put this into a column when we have js tree-table.
-      if (crypto::IsTPMTokenReady() &&
-          cert.os_cert_handle()->slot ==
-            cert_db().GetPrivateModule()->os_module_handle()) {
+      if (IsHardwareBacked(&cert)) {
         rv = l10n_util::GetStringFUTF16(
             IDS_CERT_MANAGER_HARDWARE_BACKED_KEY_FORMAT,
             rv,
             l10n_util::GetStringUTF16(IDS_CERT_MANAGER_HARDWARE_BACKED));
       }
 #endif
       break;
     case COL_CERTIFICATE_STORE:
       rv = UTF8ToUTF16(
           x509_certificate_model::GetTokenName(cert.os_cert_handle()));
@@ skipping 49 matching lines @@
     net::CertDatabase::TrustBits trust_bits) {
   return cert_db_.SetCertTrust(cert, type, trust_bits);
 }
 
 bool CertificateManagerModel::Delete(net::X509Certificate* cert) {
   bool result = cert_db_.DeleteCertAndKey(cert);
   if (result)
     Refresh();
   return result;
 }
+
+bool CertificateManagerModel::IsHardwareBacked(
+    const net::X509Certificate* cert) const {
+#if defined(OS_CHROMEOS)
+  return crypto::IsTPMTokenReady() &&
+         cert->os_cert_handle()->slot ==
+             cert_db().GetPrivateModule()->os_module_handle();
+#else
+  return false;
+#endif
+}