chrome: Cleanup class/struct forward declarations

chrome/common/extensions/command.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_COMMON_EXTENSIONS_COMMAND_H_
 #define CHROME_COMMON_EXTENSIONS_COMMAND_H_
 
 #include <map>
 #include <string>
 
 #include "base/strings/string16.h"
 #include "ui/base/accelerators/accelerator.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace extensions {
-class Extension;
-}
-
-namespace extensions {
 
 class Command {
  public:
   Command();
   Command(const std::string& command_name,
           const base::string16& description,
           const std::string& accelerator,
           bool global);
   Command(const Command& other);
   ~Command();
@@ skipping 41 matching lines @@
   base::string16 description_;
   bool global_;
 };
 
 // A mapping of command name (std::string) to a command object.
 typedef std::map<std::string, Command> CommandMap;
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_COMMAND_H_