We should use UserID object to identify users instead of username.

chrome/browser/ui/webui/help/help_handler.cc

 // Copyright (c) 2012 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/ui/webui/help/help_handler.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 90 matching lines @@
   // On a managed machine we delegate this setting to the users of the same
   // domain only if the policy value is "domain".
   if (IsEnterpriseManaged()) {
     if (!value)
       return false;
     // Get the currently logged in user and strip the domain part only.
     std::string domain = "";
     const user_manager::User* user =
         profile ? chromeos::ProfileHelper::Get()->GetUserByProfile(profile)
                 : nullptr;
-    std::string email = user ? user->email() : std::string();
+    std::string email = user ? user->GetUserID().GetUserEmail() : std::string();
     size_t at_pos = email.find('@');
     if (at_pos != std::string::npos && at_pos + 1 < email.length())
       domain = email.substr(email.find('@') + 1);
     policy::BrowserPolicyConnectorChromeOS* connector =
         g_browser_process->platform_part()->browser_policy_connector_chromeos();
     return domain == connector->GetEnterpriseDomain();
   } else {
     chromeos::OwnerSettingsServiceChromeOS* service =
         chromeos::OwnerSettingsServiceChromeOSFactory::GetInstance()
             ->GetForBrowserContext(profile);
@@ skipping 485 matching lines @@
 }
 
 void HelpHandler::OnFCCLabelTextRead(const std::string& text) {
   // Remove unnecessary whitespace.
   web_ui()->CallJavascriptFunction(
       "help.HelpPage.setProductLabelText",
       base::StringValue(base::CollapseWhitespaceASCII(text, true)));
 }
 
 #endif // defined(OS_CHROMEOS)