IsCommandIdEnabled should not fall though if the base did handle the command id

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 60 matching lines @@
 
   // 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_; }
 
+  // Sets the state of the command id in |enabled|. The function
+  // returns true if the command id is handled.
+  bool GetCommandIdEnabled(int command_id, bool* enabled) const;

[sky, 2014/08/08 16:36:23]

The description you have here and the name is mildly confusing. How about:

// Returns true if the specified command id is known and valid for this menu. If
// the command is known |enabled| is set to indicate if the command is enabled.
bool IsCommandIdKnown(int command_id, bool* enabled);

[oshima, 2014/08/08 17:14:17]

Done.

+
   // SimpleMenuModel::Delegate implementation.
   virtual bool IsCommandIdChecked(int command_id) const OVERRIDE;
-  virtual bool IsCommandIdEnabled(int command_id) const OVERRIDE;
   virtual void ExecuteCommand(int command_id, int event_flags) OVERRIDE;
   virtual void MenuWillShow(ui::SimpleMenuModel* source) OVERRIDE;
   virtual void MenuClosed(ui::SimpleMenuModel* source) OVERRIDE;
 
   // RenderViewContextMenuProxy implementation.
   virtual void AddMenuItem(int command_id,
                            const base::string16& title) OVERRIDE;
   virtual void AddCheckItem(int command_id,
                             const base::string16& title) OVERRIDE;
   virtual void AddSeparator() OVERRIDE;
@@ skipping 83 matching lines @@
   // The RenderFrameHost's IDs.
   int render_process_id_;
   int render_frame_id_;
 
   scoped_ptr<ToolkitDelegate> toolkit_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewContextMenuBase);
 };
 
 #endif  // COMPONENTS_RENDERER_CONTEXT_MENU_RENDER_VIEW_CONTEXT_MENU_BASE_H_