ios: Cleanup class/struct forward declarations

ios/chrome/browser/infobars/infobar_container_ios.h

 // Copyright 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 IOS_CHROME_BROWSER_INFOBARS_INFOBAR_CONTAINER_IOS_H_
 #define IOS_CHROME_BROWSER_INFOBARS_INFOBAR_CONTAINER_IOS_H_
 
 #include "components/infobars/core/infobar_container.h"
 
 #include <stddef.h>
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/macros.h"
 
 @class InfoBarContainerView;
-class InfoBarIOS;
 
 // IOS infobar container specialization, managing infobars visibility so
 // that only the front most one is visible at any time.
 class InfoBarContainerIOS : public infobars::InfoBarContainer {
  public:
   explicit InfoBarContainerIOS(infobars::InfoBarContainer::Delegate* delegate);
   ~InfoBarContainerIOS() override;
 
   // Returns the UIView container.
   InfoBarContainerView* view();
@@ skipping 12 matching lines @@
   void PlatformSpecificInfoBarStateChanged(bool is_animating) override;
 
  private:
   base::scoped_nsobject<InfoBarContainerView> container_view_;
   InfoBarContainer::Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarContainerIOS);
 };
 
 #endif  // IOS_CHROME_BROWSER_INFOBARS_INFOBAR_CONTAINER_IOS_H_