Move command handling and updating off Browser and onto a helper object.

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_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "webkit/glue/window_open_disposition.h"
 
+// An Observer interface implemented by objects that want to be informed when
+// the state of a particular command ID is modified.
+class CommandObserver {
+  public:

[sky, 2012/06/27 03:09:28]

nit: spacing is off here and 21.

Also, I think this class should be in its own header. But that can be done
later.

+  // Notifies the observer that the enabled state has changed for the
+  // specified command id.
+  virtual void EnabledStateChangedForCommand(int id, bool enabled) = 0;
+
+  protected:
+  virtual ~CommandObserver();
+};
+
 ////////////////////////////////////////////////////////////////////////////////
 //
 // 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:
@@ skipping 18 matching lines @@
 
   // 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.
-  // TODO(beng): get rid of this since it's effectively just a pass-thru and the
-  // call sites would be better off using more well defined delegate interfaces.
-  void ExecuteCommand(int id);
+  // Returns true if the command was executed (i.e. it is supported and is
+  // enabled).
+  bool ExecuteCommand(int id);
 
   // Performs the action associated with this command ID using the given
   // disposition.
-  // TODO(altimofeev): refactor the interface to provide more flexible and
-  // explicit way for passing command specific arguments. See
-  // NotificationDetails class for the possible implementation ideas.
-  void ExecuteCommandWithDisposition(int id, WindowOpenDisposition disposition);
-
-  // An Observer interface implemented by objects that want to be informed when
-  // the state of a particular command ID is modified.
-  class CommandObserver {
-   public:
-    // Notifies the observer that the enabled state has changed for the
-    // specified command id.
-    virtual void EnabledStateChangedForCommand(int id, bool enabled) = 0;
-
-   protected:
-    virtual ~CommandObserver();
-  };
+  // Returns true if the command was executed (i.e. it is supported and is
+  // enabled).
+  bool ExecuteCommandWithDisposition(int id, WindowOpenDisposition disposition);
 
   // Adds an observer to the state of a particular command. If the command does
   // not exist, it is created, initialized to false.
   void AddCommandObserver(int id, CommandObserver* observer);
 
   // Removes an observer to the state of a particular command.
   void RemoveCommandObserver(int id, CommandObserver* observer);
 
   // Removes |observer| for all commands on which it's registered.
   void RemoveCommandObserver(CommandObserver* observer);
@@ skipping 18 matching lines @@
 
   // 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_