Add simple mash context menu support.

ash/mus/context_menu_mus.h

Index: ash/mus/context_menu_mus.h
diff --git a/ash/shell/context_menu.h b/ash/mus/context_menu_mus.h
similarity index 60%
copy from ash/shell/context_menu.h
copy to ash/mus/context_menu_mus.h
index b604884f56d9d845e61e81d2bbbcea7b7c769355..dfe327af30ac271c830f88fbedd6d69ae939ed3e 100644
--- a/ash/shell/context_menu.h
+++ b/ash/mus/context_menu_mus.h
@@ -1,9 +1,9 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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.
 
-#ifndef ASH_SHELL_CONTEXT_MENU_H_
-#define ASH_SHELL_CONTEXT_MENU_H_
+#ifndef ASH_MUS_CONTEXT_MENU_MUS_H_
+#define ASH_MUS_CONTEXT_MENU_MUS_H_
 
 #include "ash/shelf/shelf_alignment_menu.h"
 #include "base/macros.h"
@@ -13,14 +13,13 @@ namespace ash {
 
 class Shelf;
 
-namespace shell {
-
-// Context menu for the ash shell.
-class ContextMenu : public ui::SimpleMenuModel,
-                    public ui::SimpleMenuModel::Delegate {
+// Context menu for mash.
+// TODO(msw): Mimic logic in LauncherContextMenu.
+class ContextMenuMus : public ui::SimpleMenuModel,
+                       public ui::SimpleMenuModel::Delegate {
  public:
-  explicit ContextMenu(Shelf* shelf);
-  ~ContextMenu() override;
+  explicit ContextMenuMus(Shelf* shelf);
+  ~ContextMenuMus() override;
 
   // ui::SimpleMenuModel::Delegate overrides:
   bool IsCommandIdChecked(int command_id) const override;
@@ -33,15 +32,15 @@ class ContextMenu : public ui::SimpleMenuModel,
   enum MenuItem {
     MENU_AUTO_HIDE,
     MENU_ALIGNMENT_MENU,
+    MENU_CHANGE_WALLPAPER,
   };
 
   Shelf* shelf_;
   ShelfAlignmentMenu alignment_menu_;
 
-  DISALLOW_COPY_AND_ASSIGN(ContextMenu);
+  DISALLOW_COPY_AND_ASSIGN(ContextMenuMus);
 };
 
-}  // namespace shell
 }  // namespace ash
 
-#endif  // ASH_SHELL_CONTEXT_MENU_H_
+#endif  // ASH_MUS_CONTEXT_MENU_MUS_H_