Move shelf item tooltip flag from delegate to item.

ash/common/shelf/shelf_item_types.h

Index: ash/common/shelf/shelf_item_types.h
diff --git a/ash/common/shelf/shelf_item_types.h b/ash/common/shelf/shelf_item_types.h
index 3485c212e78581a428d4af31632444067f87e018..386e979b931f46ac27994b90f81574f6882dbde2 100644
--- a/ash/common/shelf/shelf_item_types.h
+++ b/ash/common/shelf/shelf_item_types.h
@@ -56,6 +56,7 @@ enum ShelfItemStatus {
 
 struct ASH_EXPORT ShelfItem {
   ShelfItem();
+  ShelfItem(const ShelfItem& shelf_item);
   ~ShelfItem();
 
   ShelfItemType type = TYPE_UNDEFINED;
@@ -71,6 +72,9 @@ struct ASH_EXPORT ShelfItem {
 
   // The application id for this shelf item; only populated for some items.
   std::string app_id;
+
+  // Whether the tooltip should be shown on hover; generally true.
+  bool shows_tooltip = true;
 };
 
 typedef std::vector<ShelfItem> ShelfItems;