Extract NavigationManagerImpl interface for navigation experiment.

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 <memory>
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/memory/ptr_util.h"
 #import "ios/web/navigation/crw_session_controller+private_constructors.h"
 #import "ios/web/navigation/crw_session_controller.h"
+#import "ios/web/navigation/legacy_navigation_manager_impl.h"
 #import "ios/web/navigation/navigation_item_impl.h"
 #import "ios/web/navigation/navigation_item_storage_builder.h"
 #include "ios/web/navigation/navigation_manager_impl.h"
 #import "ios/web/public/crw_session_storage.h"
 #import "ios/web/public/serializable_user_data_manager.h"
 #import "ios/web/web_state/session_certificate_policy_cache_impl.h"
 #include "ios/web/web_state/session_certificate_policy_cache_storage_builder.h"
 #import "ios/web/web_state/web_state_impl.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
@@ skipping 11 matching lines @@
 namespace web {
 
 CRWSessionStorage* SessionStorageBuilder::BuildStorage(
     WebStateImpl* web_state) const {
   DCHECK(web_state);
   web::NavigationManagerImpl* navigation_manager =
       web_state->navigation_manager_.get();
   DCHECK(navigation_manager);
   CRWSessionStorage* session_storage = [[CRWSessionStorage alloc] init];
   session_storage.hasOpener = web_state->HasOpener();
-  CRWSessionController* session_controller =
-      navigation_manager->GetSessionController();
   session_storage.lastCommittedItemIndex =
-      session_controller.lastCommittedItemIndex;
-  session_storage.previousItemIndex = session_controller.previousItemIndex;
+      navigation_manager->GetLastCommittedItemIndex();
+  session_storage.previousItemIndex =
+      static_cast<NSInteger>(navigation_manager->GetPreviousItemIndex());
   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();
+  for (size_t index = 0;
+       index < static_cast<size_t>(navigation_manager->GetItemCount());
+       ++index) {
+    web::NavigationItemImpl* item =
+        navigation_manager->GetNavigationItemImplAtIndex(index);
+    ;
     [item_storages addObject:item_storage_builder.BuildStorage(item)];
   }
   session_storage.itemStorages = item_storages;
   SessionCertificatePolicyCacheStorageBuilder cert_builder;
   session_storage.certPolicyCacheStorage = cert_builder.BuildStorage(
       &web_state->GetSessionCertificatePolicyCacheImpl());
   web::SerializableUserDataManager* user_data_manager =
       web::SerializableUserDataManager::FromWebState(web_state);
   [session_storage
       setSerializableUserData:user_data_manager->CreateSerializableUserData()];
@@ skipping 14 matching lines @@
         item_storage_builder.BuildNavigationItemImpl(item_storages[index]);
     items[index] = std::move(item_impl);
   }
   NSUInteger last_committed_item_index = storage.lastCommittedItemIndex;
   base::scoped_nsobject<CRWSessionController> session_controller(
       [[CRWSessionController alloc]
             initWithBrowserState:nullptr
                  navigationItems:std::move(items)
           lastCommittedItemIndex:last_committed_item_index]);
   [session_controller setPreviousItemIndex:storage.previousItemIndex];
-  web_state->navigation_manager_.reset(new NavigationManagerImpl());
-  web_state->navigation_manager_->SetSessionController(session_controller);
+
+  auto navigation_manager = base::MakeUnique<LegacyNavigationManagerImpl>();
+  navigation_manager->SetSessionController(session_controller);
+  web_state->navigation_manager_.reset(navigation_manager.release());
+
   SessionCertificatePolicyCacheStorageBuilder cert_builder;
   std::unique_ptr<SessionCertificatePolicyCacheImpl> cert_policy_cache =
       cert_builder.BuildSessionCertificatePolicyCache(
           storage.certPolicyCacheStorage);
   if (!cert_policy_cache)
     cert_policy_cache = base::MakeUnique<SessionCertificatePolicyCacheImpl>();
   web_state->certificate_policy_cache_ = std::move(cert_policy_cache);
   web::SerializableUserDataManager::FromWebState(web_state)
       ->AddSerializableUserData(storage.userData);
 }
 
 }  // namespace web