components: Cleanup class/struct fwd declarations

components/infobars/core/infobar_manager.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 COMPONENTS_INFOBARS_CORE_INFOBAR_MANAGER_H_
 #define COMPONENTS_INFOBARS_CORE_INFOBAR_MANAGER_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "components/infobars/core/infobar_delegate.h"
 
 class ConfirmInfoBarDelegate;
 class GURL;
 
-namespace content {
-class WebContents;
-}
-
 namespace infobars {
 
 class InfoBar;
 
 // Provides access to creating, removing and enumerating info bars
 // attached to a tab.
 class InfoBarManager {
  public:
   // Observer class for infobar events.
   class Observer {
@@ skipping 94 matching lines @@
   bool infobars_enabled_;
 
   base::ObserverList<Observer, true> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarManager);
 };
 
 }  // namespace infobars
 
 #endif  // COMPONENTS_INFOBARS_CORE_INFOBAR_MANAGER_H_