mash: Support ShelfModel access in Chrome.

ash/public/cpp/shelf_item_delegate.cc

Index: ash/public/cpp/shelf_item_delegate.cc
diff --git a/ash/public/cpp/shelf_item_delegate.cc b/ash/public/cpp/shelf_item_delegate.cc
index c1fdab9f006a451c0e824c95ada958fc391d6801..471d5f387a0cf23410c23b4617f3b84ca5a0db47 100644
--- a/ash/public/cpp/shelf_item_delegate.cc
+++ b/ash/public/cpp/shelf_item_delegate.cc
@@ -7,10 +7,14 @@
 namespace ash {
 
 ShelfItemDelegate::ShelfItemDelegate(const ash::ShelfID& shelf_id)
-    : shelf_id_(shelf_id), image_set_by_controller_(false) {}
+    : shelf_id_(shelf_id), binding_(this), image_set_by_controller_(false) {}
 
 ShelfItemDelegate::~ShelfItemDelegate() {}
 
+mojom::ShelfItemDelegatePtr ShelfItemDelegate::CreateInterfacePtrAndBind() {
+  return binding_.CreateInterfacePtrAndBind();
+}
+
 MenuItemList ShelfItemDelegate::GetAppMenuItems(int event_flags) {
   return MenuItemList();
 }