[ios] Removed -[CRWSessionController goDelta:].

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.
 
 #include "ios/web/navigation/navigation_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 277 matching lines @@
 
 bool NavigationManagerImpl::CanGoBack() const {
   return CanGoToOffset(-1);
 }
 
 bool NavigationManagerImpl::CanGoForward() const {
   return CanGoToOffset(1);
 }
 
 bool NavigationManagerImpl::CanGoToOffset(int offset) const {
-  return [session_controller_ canGoDelta:offset];
+  int index = GetIndexForOffset(offset);
+  return 0 <= index && index < GetItemCount();
 }
 
 void NavigationManagerImpl::GoBack() {
   delegate_->GoToIndex(GetIndexForOffset(-1));
 }
 
 void NavigationManagerImpl::GoForward() {
   delegate_->GoToIndex(GetIndexForOffset(1));
 }
 
@@ skipping 26 matching lines @@
 void NavigationManagerImpl::CopyState(
     NavigationManagerImpl* navigation_manager) {
   SetSessionController([navigation_manager->GetSessionController() copy]);
 }
 
 int NavigationManagerImpl::GetIndexForOffset(int offset) const {
   return [session_controller_ indexOfEntryForDelta:offset];
 }
 
 }  // namespace web