Revert of chromeos: Makes mushrome use simplified display management

ash/shell_init_params.h

 // 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.
 
 #ifndef ASH_SHELL_INIT_PARAMS_H_
 #define ASH_SHELL_INIT_PARAMS_H_
 
 #include "ash/ash_export.h"
 
 namespace aura {
@@ skipping 11 matching lines @@
 namespace ash {
 
 class ShellDelegate;
 class ShellPort;
 
 struct ASH_EXPORT ShellInitParams {
   // Shell takes ownership of |shell_port|, if null ShellPortClassic is created.
   ShellPort* shell_port = nullptr;
   // Shell takes ownership of |primary_window_tree_host|. This is only used
   // by mash.
-  // TODO(sky): once simplified display management is enabled for mash this
-  // should no longer be necessary. http://crbug.com/708287.
   aura::WindowTreeHostMus* primary_window_tree_host = nullptr;
   ShellDelegate* delegate = nullptr;
   ui::ContextFactory* context_factory = nullptr;
   ui::ContextFactoryPrivate* context_factory_private = nullptr;
   base::SequencedWorkerPool* blocking_pool = nullptr;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_INIT_PARAMS_H_