Remove Downcasting RVContextMenuBase in ContextMenuDeleagate implementations.

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 <map>
 #include <string>
 
@@ skipping 51 matching lines @@
   static int ConvertToContentCustomCommandId(int id);
 
   // True if the given id is the one generated for content context menu.
   static bool IsContentCustomCommandId(int id);
 
   RenderViewContextMenuBase(content::RenderFrameHost* render_frame_host,
                             const content::ContextMenuParams& params);
 
   ~RenderViewContextMenuBase() override;
 
+  // Displays the menu.
+  // Different platform will have their own implementation.
+  virtual void Show() = 0;
+
   // Initializes the context menu.
   void Init();
 
   // Programmatically closes the context menu.
   void Cancel();
 
   const ui::SimpleMenuModel& menu_model() const { return menu_model_; }
   const content::ContextMenuParams& params() const { return params_; }
 
   // Returns true if the specified command id is known and valid for
@@ skipping 99 matching lines @@
 
   // The RenderFrameHost's IDs.
   int render_process_id_;
 
   scoped_ptr<ToolkitDelegate> toolkit_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewContextMenuBase);
 };
 
 #endif  // COMPONENTS_RENDERER_CONTEXT_MENU_RENDER_VIEW_CONTEXT_MENU_BASE_H_