mash: Migrate remaining tray observers and notify functions.

ash/common/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/common/system/update/tray_update.h"
 
-#include "ash/common/system/tray/wm_system_tray_notifier.h"
+#include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm_shell.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/test_system_tray_delegate.h"
 #include "base/macros.h"
 
 namespace ash {
 
 using TrayUpdateTest = test::AshTestBase;
 
@@ skipping 14 matching lines @@
   // Simulate an update.
   UpdateInfo info;
   info.update_required = true;
   WmShell::Get()->system_tray_notifier()->NotifyUpdateRecommended(info);
 
   // Tray item is now visible.
   EXPECT_TRUE(tray_update->tray_view()->visible());
 }
 
 }  // namespace ash