[Mac] Finish up extension infobar UI implementation.

chrome/browser/cocoa/extensions/extension_infobar_controller.h

 // Copyright (c) 2010 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_COCOA_EXTENSIONS_EXTENSION_INFOBAR_CONTROLLER_H_
 #define CHROME_BROWSER_COCOA_EXTENSIONS_EXTENSION_INFOBAR_CONTROLLER_H_
 
 #import "chrome/browser/cocoa/infobar_controller.h"
 
 #import <Cocoa/Cocoa.h>
 
+#import "base/scoped_nsobject.h"
+#include "base/scoped_ptr.h"
+
+@class ExtensionActionContextMenu;
+class ExtensionInfoBarDelegate;
+class InfobarBridge;
+@class MenuButton;
+
 @interface ExtensionInfoBarController : InfoBarController {
   // The native extension view retrieved from the extension host. Weak.
   NSView* extensionView_;
 
   // The window containing this InfoBar. Weak.
   NSWindow* window_;
+
+  // The InfoBar's button with the Extension's icon that launches the context
+  // menu.
+  scoped_nsobject<MenuButton> dropdownButton_;
+
+  // The context menu that pops up when the left button is clicked.
+  scoped_nsobject<ExtensionActionContextMenu> contextMenu_;
+
+  // Helper class to bridge C++ and ObjC functionality together for the infobar.
+  scoped_ptr<InfobarBridge> bridge_;
 }
 
 @end
 
 #endif  // CHROME_BROWSER_COCOA_EXTENSIONS_EXTENSION_INFOBAR_CONTROLLER_H_