Use mojo SystemTray interfaces for both mash and classic ash

ash/mus/shell_delegate_mus.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/mus/shell_delegate_mus.h"
 
 #include <utility>
 
 #include "ash/common/gpu_support_stub.h"
 #include "ash/common/media_delegate.h"
 #include "ash/common/palette_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
+#include "ash/common/system/tray/default_system_tray_delegate.h"
 #include "ash/common/wm_shell.h"
 #include "ash/mus/accessibility_delegate_mus.h"
 #include "ash/mus/context_menu_mus.h"
 #include "ash/mus/new_window_delegate_mus.h"
 #include "ash/mus/shelf_delegate_mus.h"
-#include "ash/mus/system_tray_delegate_mus.h"
 #include "ash/mus/wallpaper_delegate_mus.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "components/user_manager/user_info_impl.h"
 #include "ui/app_list/presenter/app_list_presenter.h"
 #include "ui/gfx/image/image.h"
 
 namespace ash {
 namespace {
@@ skipping 134 matching lines @@
 
 app_list::AppListPresenter* ShellDelegateMus::GetAppListPresenter() {
   return &app_list_presenter_;
 }
 
 ShelfDelegate* ShellDelegateMus::CreateShelfDelegate(ShelfModel* model) {
   return new ShelfDelegateMus(WmShell::Get()->shelf_model());
 }
 
 SystemTrayDelegate* ShellDelegateMus::CreateSystemTrayDelegate() {
-  return new SystemTrayDelegateMus(connector_);
+  return new DefaultSystemTrayDelegate;
 }
 
 std::unique_ptr<WallpaperDelegate> ShellDelegateMus::CreateWallpaperDelegate() {
   return base::MakeUnique<WallpaperDelegateMus>(connector_);
 }
 
 SessionStateDelegate* ShellDelegateMus::CreateSessionStateDelegate() {
   // TODO: http://crbug.com/647416.
   NOTIMPLEMENTED() << " Using a stub SessionStateDeleagte implementation";
   return new SessionStateDelegateStub;
@@ skipping 34 matching lines @@
   NOTIMPLEMENTED();
   return base::string16();
 }
 
 gfx::Image ShellDelegateMus::GetDeprecatedAcceleratorImage() const {
   NOTIMPLEMENTED();
   return gfx::Image();
 }
 
 }  // namespace ash