chrome: Cleanup class/struct forward declarations

chrome/browser/supervised_user/supervised_user_navigation_observer.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_SUPERVISED_USER_SUPERVISED_USER_NAVIGATION_OBSERVER_H_
 #define CHROME_BROWSER_SUPERVISED_USER_SUPERVISED_USER_NAVIGATION_OBSERVER_H_
 
 #include <vector>
 
 #include "base/macros.h"
 #include "chrome/browser/supervised_user/supervised_user_service_observer.h"
 #include "chrome/browser/supervised_user/supervised_user_url_filter.h"
 #include "chrome/browser/supervised_user/supervised_users.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "components/supervised_user_error_page/supervised_user_error_page.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 class SupervisedUserService;
 
 namespace content {
-class NavigationEntry;
 class NavigationHandle;
 class WebContents;
 }
 
 class SupervisedUserNavigationObserver
     : public content::WebContentsUserData<SupervisedUserNavigationObserver>,
       public content::WebContentsObserver,
       public SupervisedUserServiceObserver {
  public:
   ~SupervisedUserNavigationObserver() override;
@@ skipping 39 matching lines @@
 
   std::vector<std::unique_ptr<const sessions::SerializedNavigationEntry>>
       blocked_navigations_;
 
   base::WeakPtrFactory<SupervisedUserNavigationObserver> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SupervisedUserNavigationObserver);
 };
 
 #endif  // CHROME_BROWSER_SUPERVISED_USER_SUPERVISED_USER_NAVIGATION_OBSERVER_H_