ios: Cleanup class/struct forward declarations

ios/web/navigation/navigation_manager_facade_delegate.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 IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_FACADE_DELEGATE_H_
 #define IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_FACADE_DELEGATE_H_
 
 #include <stddef.h>
 
 namespace content {
 class NavigationController;
 }
 
 namespace web {
 
-class NavigationItemImpl;
 class NavigationManagerImpl;
 
 // Interface used by the NavigationManager to drive the NavigationController
 // facade. This pushes the ownership of the facade out of the web-layer to
 // simplify upstreaming efforts.  Once upstream features are componentized and
 // use NavigationManager, this class will no longer be necessary.
 class NavigationManagerFacadeDelegate {
  public:
   NavigationManagerFacadeDelegate() {}
   virtual ~NavigationManagerFacadeDelegate() {}
@@ skipping 13 matching lines @@
   // Called when the NavigationManager has committed a pending NavigationItem.
   virtual void OnNavigationItemCommitted(int previous_item_index,
                                          bool is_in_page) = 0;
   // Called when the NavigationManager has pruned committed NavigationItems.
   virtual void OnNavigationItemsPruned(size_t pruned_item_count) = 0;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_FACADE_DELEGATE_H_