Move Extension into extensions namespace

chrome/browser/ui/cocoa/extensions/extension_install_dialog_controller.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_UI_COCOA_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLER_H_
 #define CHROME_BROWSER_UI_COCOA_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLER_H_
 #pragma once
 
 #include <vector>
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/string16.h"
 #include "chrome/browser/extensions/extension_install_ui.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
-class Extension;
 class Profile;
 
 // Displays the extension or bundle install prompt, and notifies the
 // ExtensionInstallUI::Delegate of success or failure.
 @interface ExtensionInstallDialogController : NSWindowController {
  @private
   IBOutlet NSImageView* iconView_;
   IBOutlet NSTextField* titleField_;
   IBOutlet NSTextField* itemsField_;
   IBOutlet NSButton* cancelButton_;
@@ skipping 33 matching lines @@
                   delegate:(ExtensionInstallUI::Delegate*)delegate
                     prompt:(const ExtensionInstallUI::Prompt&)prompt;
 - (void)runAsModalSheet;
 - (IBAction)storeLinkClicked:(id)sender; // Callback for "View details" link.
 - (IBAction)cancel:(id)sender;
 - (IBAction)ok:(id)sender;
 
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLLER_H_