mash: Fix ShelfItem mojo struct; add enums and traits.

ash/shell/window_watcher_shelf_item_delegate.h

 // Copyright 2013 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_WINDOW_WATCHER_SHELF_ITEM_DELEGATE_H_
 #define ASH_SHELL_WINDOW_WATCHER_SHELF_ITEM_DELEGATE_H_
 
-#include "ash/common/shelf/shelf_item_types.h"
+#include "ash/public/cpp/shelf_item.h"
 #include "ash/public/interfaces/shelf.mojom.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 
 namespace ash {
 namespace shell {
 
 class WindowWatcher;
 
 // ShelfItemDelegate implementation used by WindowWatcher.
@@ skipping 14 matching lines @@
   ShelfID id_;
   WindowWatcher* watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowWatcherShelfItemDelegate);
 };
 
 }  // namespace shell
 }  // namespace ash
 
 #endif  // ASH_SHELL_WINDOW_WATCHER_SHELF_ITEM_DELEGATE_H_