chrome: Extract CommandUpdaterDelegate into its own header file.

chrome/browser/command_updater.h

 // Copyright (c) 2012 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 CHROME_BROWSER_COMMAND_UPDATER_H_
 #define CHROME_BROWSER_COMMAND_UPDATER_H_
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "webkit/glue/window_open_disposition.h"
 
 class CommandObserver;
+class CommandUpdaterDelegate;
 
 ////////////////////////////////////////////////////////////////////////////////
 //
 // CommandUpdater class
 //
 //   This object manages the enabled state of a set of commands. Observers
 //   register to listen to changes in this state so they can update their
 //   presentation.
 //
 class CommandUpdater {
  public:
-  // A Delegate object implements this interface so that it can execute commands
-  // when needed.
-  class CommandUpdaterDelegate {
-   public:
-    // Performs the action associated with the command with the specified ID and
-    // using the given disposition.
-    virtual void ExecuteCommandWithDisposition(
-        int id,
-        WindowOpenDisposition disposition) = 0;
-
-   protected:
-    virtual ~CommandUpdaterDelegate();
-  };
-
-  // Create a CommandUpdater with a CommandUpdaterDelegate to handle execution
-  // of specific commands.
-  explicit CommandUpdater(CommandUpdaterDelegate* handler);
-  virtual ~CommandUpdater();
+  // Create a CommandUpdater with |delegate| to handle the execution of specific
+  // commands.
+  explicit CommandUpdater(CommandUpdaterDelegate* delegate);
+  ~CommandUpdater();

[sky, 2012/12/06 01:38:08]

In general if there are subclasses we make the destructor virtual. While we some
times deviate from this, in general we don't.

[tfarina, 2012/12/06 01:41:40]

If I understand you, and you are concerned about that I made the destructor of
CommandUpdater non-virtual was because it doesn't have virtual methods and
NOBODY inherits from CommandUpdater.

The one inherited is CommandUpdaterDelegate and that interface has a virtual
destructor :)

Was that your concern?

 
   // Returns true if the specified command ID is supported.
   bool SupportsCommand(int id) const;
 
   // Returns true if the specified command ID is enabled. The command ID must be
   // supported by this updater.
   bool IsCommandEnabled(int id) const;
 
   // Performs the action associated with this command ID using CURRENT_TAB
   // disposition.
@@ skipping 32 matching lines @@
   // exist if desired.
   Command* GetCommand(int id, bool create);
 
   // The delegate is responsible for executing commands.
   CommandUpdaterDelegate* delegate_;
 
   // This is a map of command IDs to states and observer lists
   typedef base::hash_map<int, Command*> CommandMap;
   CommandMap commands_;
 
-  CommandUpdater();
   DISALLOW_COPY_AND_ASSIGN(CommandUpdater);
 };
 
 #endif  // CHROME_BROWSER_COMMAND_UPDATER_H_