No need to pass DownloadItemModel ownership.

chrome/browser/ui/gtk/download/download_shelf_context_menu_gtk.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/download/download_shelf_context_menu_gtk.h"
 
 #include "base/logging.h"
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/ui/gtk/download/download_item_gtk.h"
 #include "content/public/browser/page_navigator.h"
 #include "ui/gfx/point.h"
 
 DownloadShelfContextMenuGtk::DownloadShelfContextMenuGtk(
-    DownloadItemModel* model,
     DownloadItemGtk* download_item,
     content::PageNavigator* navigator)
-    : DownloadShelfContextMenu(model, navigator),
+    : DownloadShelfContextMenu(download_item->download(), navigator),
       download_item_gtk_(download_item) {
 }
 
 DownloadShelfContextMenuGtk::~DownloadShelfContextMenuGtk() {}
 
 void DownloadShelfContextMenuGtk::Popup(GtkWidget* widget,
                                         GdkEventButton* event) {
-  menu_.reset(new MenuGtk(this, GetMenuModel()));
+  ui::SimpleMenuModel* menu_model = GetMenuModel();
+  // Popup() should never be called after the DownloadItem is destroyed.
+  DCHECK(menu_model);
+
+  menu_.reset(new MenuGtk(this, menu_model));
 
   if (widget)
     menu_->PopupForWidget(widget, event->button, event->time);
   else
     menu_->PopupAsContext(gfx::Point(event->x_root, event->y_root),
                           event->time);
 }
 
 void DownloadShelfContextMenuGtk::StoppedShowing() {
   download_item_gtk_->menu_showing_ = false;
@@ skipping 17 matching lines @@
     case TOGGLE_PAUSE:
       stock = NULL;
       break;
 
     default:
       NOTREACHED();
       break;
   }
   return stock ? gtk_image_new_from_stock(stock, GTK_ICON_SIZE_MENU) : NULL;
 }