Revert "chromeos: Move files in //ash/common to //ash, part 3"

ash/system/update/tray_update_unittest.cc

 // Copyright 2016 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/update/tray_update.h"
 
+#include "ash/common/wm_shell.h"
 #include "ash/public/interfaces/update.mojom.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_controller.h"
 #include "ash/test/ash_test.h"
-#include "ash/wm_shell.h"
 
 namespace ash {
 
 using TrayUpdateTest = AshTest;
 
 // Tests that the update icon becomes visible when an update becomes
 // available.
 TEST_F(TrayUpdateTest, VisibilityAfterUpdate) {
   TrayUpdate* tray_update = GetPrimarySystemTray()->tray_update();
 
   // The system starts with no update pending, so the icon isn't visible.
   EXPECT_FALSE(tray_update->tray_view()->visible());
 
   // Simulate an update.
   WmShell::Get()->system_tray_controller()->ShowUpdateIcon(
       mojom::UpdateSeverity::LOW, false);
 
   // Tray item is now visible.
   EXPECT_TRUE(tray_update->tray_view()->visible());
 }
 
 }  // namespace ash