Remove the concept of currentItemIndex

ios/web/navigation/navigation_manager_impl.mm

 // Copyright 2013 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/navigation_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 257 matching lines @@
 }
 
 int NavigationManagerImpl::GetItemCount() const {
   return [session_controller_ items].size();
 }
 
 NavigationItem* NavigationManagerImpl::GetItemAtIndex(size_t index) const {
   return [session_controller_ itemAtIndex:index];
 }
 
-int NavigationManagerImpl::GetCurrentItemIndex() const {
-  return [session_controller_ currentNavigationIndex];
-}
-
 int NavigationManagerImpl::GetPendingItemIndex() const {
   if (GetPendingItem()) {
     if ([session_controller_ pendingItemIndex] != -1) {
       return [session_controller_ pendingItemIndex];
     }
-    // TODO(crbug.com/665189): understand why current item index is
+    // TODO(crbug.com/665189): understand why last committed item index is
     // returned here.
-    return GetCurrentItemIndex();
+    return GetLastCommittedItemIndex();
   }
   return -1;
 }
 
 int NavigationManagerImpl::GetLastCommittedItemIndex() const {
   if (GetItemCount() == 0)
     return -1;
   return [session_controller_ currentNavigationIndex];
 }
 
@@ skipping 62 matching lines @@
 NavigationManagerImpl::GetTransientURLRewriters() {
   return std::move(transient_url_rewriters_);
 }
 
 void NavigationManagerImpl::RemoveTransientURLRewriters() {
   transient_url_rewriters_.reset();
 }
 
 int NavigationManagerImpl::GetIndexForOffset(int offset) const {
   int result = [session_controller_ pendingItemIndex] == -1
-                   ? GetCurrentItemIndex()
+                   ? GetLastCommittedItemIndex()
                    : static_cast<int>([session_controller_ pendingItemIndex]);
 
   if (offset < 0) {
     if (GetTransientItem() && [session_controller_ pendingItemIndex] == -1) {
       // Going back from transient item that added to the end navigation stack
       // is a matter of discarding it as there is no need to move navigation
       // index back.
       offset++;
     }
 
@@ skipping 56 matching lines @@
 
 bool NavigationManagerImpl::IsRedirectItemAtIndex(int index) const {
   DCHECK_GT(index, 0);
   DCHECK_LT(index, GetItemCount());
   ui::PageTransition transition = GetItemAtIndex(index)->GetTransitionType();
   return transition & ui::PAGE_TRANSITION_IS_REDIRECT_MASK;
 }
 
 NavigationItem* NavigationManagerImpl::GetLastCommittedNonAppSpecificItem()
     const {
-  int index = GetCurrentItemIndex();
+  int index = GetLastCommittedItemIndex();
   if (index == -1)
     return nullptr;
   WebClient* client = GetWebClient();
   const ScopedNavigationItemImplList& items = [session_controller_ items];
   while (index >= 0) {
     NavigationItem* item = items[index--].get();
     if (!client->IsAppSpecificURL(item->GetVirtualURL()))
       return item;
   }
   return nullptr;
 }
 
 }  // namespace web