components: Cleanup class/struct fwd declarations

components/dom_distiller/ios/distiller_page_factory_ios.h

 // Copyright 2015 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_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_
 #define COMPONENTS_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_
 
 #include <memory>
 
 #include "components/dom_distiller/core/distiller_page.h"
 
 namespace web {
 class BrowserState;
 }
 
 namespace dom_distiller {
 
-class DistillerPageIOS;
-
 // DistillerPageFactoryIOS is an iOS-specific implementation of the
 // DistillerPageFactory interface allowing the creation of DistillerPage
 // instances.
 class DistillerPageFactoryIOS : public DistillerPageFactory {
  public:
   DistillerPageFactoryIOS(web::BrowserState* browser_state);
 
   // Implementation of DistillerPageFactory:
   std::unique_ptr<DistillerPage> CreateDistillerPage(
       const gfx::Size& view_size) const override;
   std::unique_ptr<DistillerPage> CreateDistillerPageWithHandle(
       std::unique_ptr<SourcePageHandle> handle) const override;
 
  private:
   web::BrowserState* browser_state_;
 };
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_