chrome: Cleanup class/struct forward declarations

chrome/browser/ui/toolbar/toolbar_actions_bar.h

 // Copyright 2014 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_TOOLBAR_TOOLBAR_ACTIONS_BAR_H_
 #define CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_BAR_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/scoped_observer.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/toolbar/toolbar_actions_bar_bubble_delegate.h"
 #include "chrome/browser/ui/toolbar/toolbar_actions_model.h"
 #include "ui/gfx/animation/tween.h"
 #include "ui/gfx/geometry/size.h"
 
-namespace extensions {
-class Extension;
-class ExtensionMessageBubbleController;
-}
-
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 class ToolbarActionsBarDelegate;
 class ToolbarActionsBarObserver;
 class ToolbarActionViewController;
 
 // A platform-independent version of the container for toolbar actions,
 // including extension actions and component actions.
@@ skipping 327 matching lines @@
   ScopedObserver<TabStripModel, TabStripModelObserver> tab_strip_observer_;
 
   base::ObserverList<ToolbarActionsBarObserver> observers_;
 
   base::WeakPtrFactory<ToolbarActionsBar> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ToolbarActionsBar);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_BAR_H_