mash: Migrate SessionStateDelegate access to WmShell.

ash/system/overview/overview_button_tray_unittest.cc

 // Copyright 2014 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/overview/overview_button_tray.h"
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/login_status.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/common/wm/overview/window_selector_controller.h"
@@ skipping 56 matching lines @@
 };
 
 void OverviewButtonTrayTest::SetUp() {
   base::CommandLine::ForCurrentProcess()->AppendSwitch(
       switches::kAshUseFirstDisplayAsInternal);
   AshTestBase::SetUp();
 }
 
 void OverviewButtonTrayTest::NotifySessionStateChanged() {
   GetTray()->SessionStateChanged(
-      ash_test_helper()->GetTestSessionStateDelegate()->GetSessionState());
+      test::AshTestHelper::GetTestSessionStateDelegate()->GetSessionState());
 }
 
 // Ensures that creation doesn't cause any crashes and adds the image icon.
 TEST_F(OverviewButtonTrayTest, BasicConstruction) {
   EXPECT_TRUE(GetImageView(GetTray()) != NULL);
 }
 
 // Test that maximize mode toggle changes visibility.
 // OverviewButtonTray should only be visible when MaximizeMode is enabled.
 // By default the system should not have MaximizeMode enabled.
@@ skipping 182 matching lines @@
       ->maximize_mode_controller()
       ->EnableMaximizeModeWindowManager(true);
   EXPECT_TRUE(GetTray()->visible());
   Shell::GetInstance()
       ->maximize_mode_controller()
       ->EnableMaximizeModeWindowManager(false);
   EXPECT_FALSE(GetTray()->visible());
 }
 
 }  // namespace ash