Move download messages from Renderer to Frame filter.

components/renderer_context_menu/render_view_context_menu_base.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_RENDERER_CONTEXT_MENU_RENDER_VIEW_CONTEXT_MENU_BASE_H_
 #define COMPONENTS_RENDERER_CONTEXT_MENU_RENDER_VIEW_CONTEXT_MENU_BASE_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 142 matching lines @@
                                   ui::Accelerator* accelerator) override = 0;
 
   // Subclasses should send notification.
   virtual void NotifyMenuShown() = 0;
   virtual void NotifyURLOpened(const GURL& url,
                                content::WebContents* new_contents) = 0;
 
   // TODO(oshima): Remove this.
   virtual void AppendPlatformEditableItems() {}
 
+  // May return nullptr if the frame was deleted while the menu was open.
   content::RenderFrameHost* GetRenderFrameHost();
 
   bool IsCustomItemChecked(int id) const;
   bool IsCustomItemEnabled(int id) const;
 
   // Opens the specified URL string in a new tab.
   void OpenURL(const GURL& url, const GURL& referrer,
                WindowOpenDisposition disposition,
                ui::PageTransition transition);
 
@@ skipping 29 matching lines @@
   const int render_process_id_;
 
   std::unique_ptr<ToolkitDelegate> toolkit_delegate_;
 
   ScopedVector<ui::SimpleMenuModel> custom_submenus_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewContextMenuBase);
 };
 
 #endif  // COMPONENTS_RENDERER_CONTEXT_MENU_RENDER_VIEW_CONTEXT_MENU_BASE_H_