Remove the concept of currentItemIndex

ios/web/navigation/crw_session_storage_unittest.mm

Index: ios/web/navigation/crw_session_storage_unittest.mm
diff --git a/ios/web/navigation/crw_session_storage_unittest.mm b/ios/web/navigation/crw_session_storage_unittest.mm
index ab17ff766631756073efe1210330dc09c10c9ac4..c8a698df41c955962393f245c80469bc06c88a2b 100644
--- a/ios/web/navigation/crw_session_storage_unittest.mm
+++ b/ios/web/navigation/crw_session_storage_unittest.mm
@@ -49,8 +49,8 @@ BOOL SessionStoragesAreEqual(CRWSessionStorage* session1,
   NSArray* items2 = session2.itemStorages;
   return ItemStorageListsAreEqual(items1, items2) &&
          session1.hasOpener == session2.hasOpener &&
-         session1.currentNavigationIndex == session2.currentNavigationIndex &&
-         session1.previousNavigationIndex == session2.previousNavigationIndex &&
+         session1.lastCommittedItemIndex == session2.lastCommittedItemIndex &&
+         session1.previousItemIndex == session2.previousItemIndex &&
          UserDataAreEqual(session1.userData, session2.userData);
 }
 }  // namespace
@@ -61,8 +61,8 @@ BOOL SessionStoragesAreEqual(CRWSessionStorage* session1,
       : session_storage_([[CRWSessionStorage alloc] init]) {
     // Set up |session_storage_|.
     [session_storage_ setHasOpener:YES];
-    [session_storage_ setCurrentNavigationIndex:4];
-    [session_storage_ setPreviousNavigationIndex:3];
+    [session_storage_ setLastCommittedItemIndex:4];
+    [session_storage_ setPreviousItemIndex:3];
     // Create an item storage.
     base::scoped_nsobject<CRWNavigationItemStorage> item_storage(
         [[CRWNavigationItemStorage alloc] init]);