Copy max_restored_page_id_ when needed.

content/browser/frame_host/navigation_controller_impl.cc

 // 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 "content/browser/frame_host/navigation_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"  // Temporary
@@ skipping 1298 matching lines @@
   last_committed_entry_index_ = GetEntryCount() - 1;
 
   delegate_->SetHistoryLengthAndPrune(site_instance.get(),
                                       max_source_index,
                                       minimum_page_id);
 
   // Copy the max page id map from the old tab to the new tab.  This ensures
   // that new and existing navigations in the tab's current SiteInstances
   // are identified properly.
   delegate_->CopyMaxPageIDsFrom(source->delegate()->GetWebContents());
+  max_restored_page_id_ = source->max_restored_page_id_;
 
   // If there is a last committed entry, be sure to include it in the new
   // max page ID map.
   if (max_page_id > -1) {
     delegate_->UpdateMaxPageIDForSiteInstance(site_instance.get(),
                                               max_page_id);
   }
 }
 
 bool NavigationControllerImpl::CanPruneAllButLastCommitted() {
@@ skipping 414 matching lines @@
     }
   }
 }
 
 void NavigationControllerImpl::SetGetTimestampCallbackForTest(
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 }  // namespace content