chromeos: Introduce ash::SystemTrayTestApi

ash/system/enterprise/tray_enterprise_unittest.cc

 // Copyright 2017 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 "ash/system/enterprise/tray_enterprise.h"
 
 #include "ash/shell.h"
 #include "ash/system/tray/label_tray_view.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_controller.h"
+#include "ash/system/tray/system_tray_test_api.h"
 #include "ash/test/ash_test_base.h"
 
 namespace ash {
 
 using TrayEnterpriseTest = test::AshTestBase;
 
 TEST_F(TrayEnterpriseTest, ItemVisible) {
   SystemTray* system_tray = GetPrimarySystemTray();
-  TrayEnterprise* tray_enterprise = system_tray->GetTrayEnterpriseForTesting();
+  TrayEnterprise* tray_enterprise =
+      SystemTrayTestApi(system_tray).tray_enterprise();
 
   // By default there is no enterprise item in the menu.
   system_tray->ShowDefaultView(BUBBLE_CREATE_NEW);
   EXPECT_FALSE(tray_enterprise->tray_view()->visible());
   system_tray->CloseSystemBubble();
 
   // Simulate enterprise information becoming available.
   const bool active_directory = false;
   Shell::Get()->system_tray_controller()->SetEnterpriseDomain("example.com",
                                                               active_directory);
 
   // Enterprise managed devices show an item.
   system_tray->ShowDefaultView(BUBBLE_CREATE_NEW);
   EXPECT_TRUE(tray_enterprise->tray_view()->visible());
   system_tray->CloseSystemBubble();
 }
 
 TEST_F(TrayEnterpriseTest, ItemVisibleForActiveDirectory) {
   SystemTray* system_tray = GetPrimarySystemTray();
-  TrayEnterprise* tray_enterprise = system_tray->GetTrayEnterpriseForTesting();
+  TrayEnterprise* tray_enterprise =
+      SystemTrayTestApi(system_tray).tray_enterprise();
 
   // Simulate enterprise information becoming available. Active Directory
   // devices do not have a domain.
   const std::string empty_domain;
   const bool active_directory = true;
   Shell::Get()->system_tray_controller()->SetEnterpriseDomain(empty_domain,
                                                               active_directory);
 
   // Active Directory managed devices show an item.
   system_tray->ShowDefaultView(BUBBLE_CREATE_NEW);
   EXPECT_TRUE(tray_enterprise->tray_view()->visible());
   system_tray->CloseSystemBubble();
 }
 
 }  // namespace ash