[Mac] Add option to reauthenticate the OS user before revealing passwords.

chrome/browser/password_manager/password_manager_util_mac.mm

+// Copyright (c) 2013 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/password_manager/password_manager_util.h"
+
+#import <Foundation/Foundation.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/Authorization.h>
+
+#include "base/basictypes.h"
+#include "base/mac/authorization_util.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_authorizationref.h"
+#include "grit/chromium_strings.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace password_manager_util {
+
+bool AuthenticateUser() {
+  AuthorizationItem right_items[] = {
+    {"com.google.Chrome.show-passwords", 0, NULL, 0}
+  };
+  AuthorizationRights rights = {arraysize(right_items), right_items};
+
+  NSString* prompt =
+      l10n_util::GetNSString(IDS_PASSWORDS_PAGE_AUTHENTICATION_PROMPT);
+
+  // Pass kAuthorizationFlagDestroyRights to prevent the OS from saving the
+  // authorization and not prompting the user when future requests are made.
+  base::mac::ScopedAuthorizationRef authorization(
+      base::mac::GetAuthorizationRightsWithPrompt(
+          &rights, base::mac::NSToCFCast(prompt),
+          kAuthorizationFlagDestroyRights));
+  return authorization.get() != NULL;
+}
+
+}  // namespace password_manager_util