Ensure X509Certificate::OSCertHandles are safe to be used on both UI and IO threads on Win

chrome/browser/ui/views/certificate_viewer_win.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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_viewer.h"
 
 #include <windows.h>
 #include <cryptuiapi.h>
 #pragma comment(lib, "cryptui.lib")
 
+#include "base/logging.h"
 #include "net/base/x509_certificate.h"
+#include "net/base/x509_util_win.h"
 
 void ShowCertificateViewer(gfx::NativeWindow parent,
                            net::X509Certificate* cert) {
+  PCCERT_CONTEXT cert_list = net::x509_util::CreateOSCertChainForCert(cert);
+  CHECK(cert_list);
+
   CRYPTUI_VIEWCERTIFICATE_STRUCT view_info = { 0 };
   view_info.dwSize = sizeof(view_info);
   // We set our parent to the tab window. This makes the cert dialog created
   // in CryptUIDlgViewCertificate modal to the browser.
   view_info.hwndParent = parent;
   view_info.dwFlags = CRYPTUI_DISABLE_EDITPROPERTIES |
                       CRYPTUI_DISABLE_ADDTOSTORE;
-  view_info.pCertContext = cert->os_cert_handle();
+  view_info.pCertContext = cert_list;
   // Search the cert store that 'cert' is in when building the cert chain.

[wtc, 2011/10/16 14:55:49]

Nit: this comment sounds weird since the code now uses
'cert_list', not 'cert'.  Also, the cert store is now
specifically constructed for this operation.

We should update this comment (e.g., "Search the cert
store that contains the cert and its intermediate CAs
when building the cert chain").  But I think we can also
simply remove the comment.

-  HCERTSTORE cert_store = view_info.pCertContext->hCertStore;
+  HCERTSTORE cert_store = cert_list->hCertStore;
   view_info.cStores = 1;
   view_info.rghStores = &cert_store;
   BOOL properties_changed;
 
   // This next call blocks but keeps processing windows messages, making it
   // modal to the browser window.
   BOOL rv = ::CryptUIDlgViewCertificate(&view_info, &properties_changed);
+
+  CertFreeCertificateContext(cert_list);
 }