[ash] Add TYPE_DIALOG and its item's LauncherContextMenu

ash/shelf/app_list_shelf_item_delegate.cc

Index: ash/shelf/app_list_shelf_item_delegate.cc
diff --git a/ash/shelf/app_list_shelf_item_delegate.cc b/ash/shelf/app_list_shelf_item_delegate.cc
index 8d56de6f797eae7769d16815e38f88655063d856..51562ca05ca0ace59644f140b6a4a6556fca3fc2 100644
--- a/ash/shelf/app_list_shelf_item_delegate.cc
+++ b/ash/shelf/app_list_shelf_item_delegate.cc
@@ -39,7 +39,9 @@ base::string16 AppListShelfItemDelegate::GetTitle() {
 
 ui::MenuModel* AppListShelfItemDelegate::CreateContextMenu(
     aura::Window* root_window) {
-  return Shell::GetInstance()->delegate()->CreateContextMenu(root_window);
+  return Shell::GetInstance()->delegate()->CreateContextMenu(root_window,
+                                                             NULL,
+                                                             NULL);
 }
 
 ShelfMenuModel* AppListShelfItemDelegate::CreateApplicationMenu(
@@ -56,5 +58,8 @@ bool AppListShelfItemDelegate::ShouldShowTooltip() {
   return true;
 }
 
+void AppListShelfItemDelegate::Close() {
+}
+
 }  // namespace internal
 }  // namespace ash