Replace ShelfItemDelegate::GetTitle() with ShelfItem::title.

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 998f33beddba4eae25a0096b7ba3200dc742c1ee..ea021bb7d78c9b6cb019ffe1af3037c6c1bf7009 100644
--- a/ash/common/shelf/shelf_item_types.h
+++ b/ash/common/shelf/shelf_item_types.h
@@ -10,6 +10,7 @@
 
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_constants.h"
+#include "base/strings/string16.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace ash {
@@ -73,6 +74,9 @@ struct ASH_EXPORT ShelfItem {
   // The application id for this shelf item; only populated for some items.
   std::string app_id;
 
+  // The title to display for tooltips, etc.
+  base::string16 title;
+
   // Whether the tooltip should be shown on hover; generally true.
   bool shows_tooltip = true;