Remove the concept of currentItemIndex

ios/web/navigation/crw_session_controller+private_constructors.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_CRW_SESSION_CONTROLLER_PRIVATE_CONSTRUCTORS_H_
 #define IOS_WEB_NAVIGATION_CRW_SESSION_CONTROLLER_PRIVATE_CONSTRUCTORS_H_
 
 #include <memory>
 #include <vector>
 
 #import "ios/web/navigation/crw_session_controller.h"
 #include "ios/web/public/navigation_item_list.h"
 
 namespace web {
 class BrowserState;
 class NavigationItem;
 }
 
 // Temporary interface for NavigationManager and tests to create
 // CRWSessionControllers. Once CRWSessionController has no users outside of
 // web/, these methods can go back into session_controller.h. crbug.com/318974
 @interface CRWSessionController (PrivateConstructors)
 // Initializes a session controller.
 - (instancetype)initWithBrowserState:(web::BrowserState*)browserState;
 
 // Initializes a session controller, supplying a list of NavigationItem objects
-// and the current index in the navigation history.
+// and the last committed item index in the navigation history.
 - (instancetype)initWithBrowserState:(web::BrowserState*)browserState
                      navigationItems:(web::ScopedNavigationItemList)items
-                        currentIndex:(NSUInteger)currentIndex;
+              lastCommittedItemIndex:(NSUInteger)lastCommittedItemIndex;
 @end
 
 #endif  // IOS_WEB_NAVIGATION_CRW_SESSION_CONTROLLER_PRIVATE_CONSTRUCTORS_H_