mash: Port mojo:ash_sysui's ContextMenuMus to mojo:ash.

ash/shell/shell_delegate_impl.h

 // Copyright (c) 2012 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_SHELL_DELEGATE_IMPL_H_
 #define ASH_SHELL_SHELL_DELEGATE_IMPL_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 24 matching lines @@
   bool CanShowWindowForUser(WmWindow* window) const override;
   bool IsForceMaximizeOnFirstRun() const override;
   void PreInit() override;
   void PreShutdown() override;
   void Exit() override;
   keyboard::KeyboardUI* CreateKeyboardUI() override;
   void OpenUrlFromArc(const GURL& url) override;
   app_list::AppListPresenter* GetAppListPresenter() override;
   ShelfDelegate* CreateShelfDelegate(ShelfModel* model) override;
   SystemTrayDelegate* CreateSystemTrayDelegate() override;
-  UserWallpaperDelegate* CreateUserWallpaperDelegate() override;
+  std::unique_ptr<WallpaperDelegate> CreateWallpaperDelegate() override;
   SessionStateDelegate* CreateSessionStateDelegate() override;
   AccessibilityDelegate* CreateAccessibilityDelegate() override;
   NewWindowDelegate* CreateNewWindowDelegate() override;
   MediaDelegate* CreateMediaDelegate() override;
   std::unique_ptr<PaletteDelegate> CreatePaletteDelegate() override;
   ui::MenuModel* CreateContextMenu(WmShelf* wm_shelf,
                                    const ShelfItem* item) override;
   GPUSupport* CreateGPUSupport() override;
   base::string16 GetProductName() const override;
   gfx::Image GetDeprecatedAcceleratorImage() const override;
 
  private:
   ShelfDelegate* shelf_delegate_;
   std::unique_ptr<app_list::AppListPresenterDelegateFactory>
       app_list_presenter_delegate_factory_;
   std::unique_ptr<app_list::AppListPresenterImpl> app_list_presenter_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDelegateImpl);
 };
 
 }  // namespace shell
 }  // namespace ash
 
 #endif  // ASH_SHELL_SHELL_DELEGATE_IMPL_H_