Revert "Updated ownership of NavigationItems within CRWSessionController."

ios/web/navigation/session_storage_builder.mm

 // 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.
 
 #import "ios/web/navigation/session_storage_builder.h"
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #import "ios/web/navigation/crw_session_controller+private_constructors.h"
 #import "ios/web/navigation/crw_session_controller.h"
@@ skipping 41 matching lines @@
       session_controller.currentNavigationIndex;
   serialized_navigation_manager.previousNavigationIndex =
       session_controller.previousNavigationIndex;
   serialized_navigation_manager.lastVisitedTimestamp =
       session_controller.lastVisitedTimestamp;
   serialized_navigation_manager.sessionCertificatePolicyManager =
       session_controller.sessionCertificatePolicyManager;
   NSMutableArray* item_storages = [[NSMutableArray alloc] init];
   NavigationItemStorageBuilder item_storage_builder;
   for (size_t index = 0; index < session_controller.items.size(); ++index) {
-    web::NavigationItemImpl* item = session_controller.items[index].get();
+    web::NavigationItemImpl* item =
+        static_cast<web::NavigationItemImpl*>(session_controller.items[index]);
     [item_storages addObject:item_storage_builder.BuildStorage(item)];
   }
   serialized_navigation_manager.itemStorages = item_storages;
   web::SerializableUserDataManager* user_data_manager =
       web::SerializableUserDataManager::FromWebState(web_state);
   [serialized_navigation_manager
       setSerializableUserData:user_data_manager->CreateSerializableUserData()];
   return serialized_navigation_manager;
 }
 
@@ skipping 26 matching lines @@
   [session_controller
       setSessionCertificatePolicyManager:storage
                                              .sessionCertificatePolicyManager];
   web_state->navigation_manager_.reset(new NavigationManagerImpl());
   web_state->navigation_manager_->SetSessionController(session_controller);
   web::SerializableUserDataManager::FromWebState(web_state)
       ->AddSerializableUserData(storage.userData);
 }
 
 }  // namespace web