mash: Use mojo for ShelfItemDelegate and [app] MenuItem.

ash/common/shelf/shelf_window_watcher.cc

Index: ash/common/shelf/shelf_window_watcher.cc
diff --git a/ash/common/shelf/shelf_window_watcher.cc b/ash/common/shelf/shelf_window_watcher.cc
index 7a00df9d0f3af50728835d8dd96b9ca530a02e36..5681e4361967703f36deb42cec422381daec7d05 100644
--- a/ash/common/shelf/shelf_window_watcher.cc
+++ b/ash/common/shelf/shelf_window_watcher.cc
@@ -156,9 +156,9 @@ void ShelfWindowWatcher::AddShelfItem(aura::Window* window) {
   ShelfID id = model_->next_id();
   UpdateShelfItemForWindow(&item, window);
   window->SetProperty(kShelfIDKey, id);
-  std::unique_ptr<ShelfItemDelegate> item_delegate(
-      new ShelfWindowWatcherItemDelegate(id, WmWindow::Get(window)));
-  model_->SetShelfItemDelegate(id, std::move(item_delegate));
+  model_->SetShelfItemDelegate(id,
+                               base::MakeUnique<ShelfWindowWatcherItemDelegate>(
+                                   id, WmWindow::Get(window)));
   // Panels are inserted on the left so as not to push all existing panels over.
   model_->AddAt(item.type == TYPE_APP_PANEL ? 0 : model_->item_count(), item);
 }