Converts mash to use Shell

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 {
+class WindowTreeHostMus;
+}
+
 namespace base {
 class SequencedWorkerPool;
 }
 
 namespace ui {
 class ContextFactory;
 }
 
 namespace ash {
 
 class ShellDelegate;
 
 struct ASH_EXPORT ShellInitParams {
+  // Shell takes ownership of |wm_shell|, if null WmShellAura is created.
+  // TODO(sky): temporary, will eventually go away.
+  WmShell* wm_shell = nullptr;
+  // Shell takes ownership of |primary_window_tree_host|. This is only used
+  // by mash.
+  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_