Fix NavigationControllerBrowserTest.SubframeForwardRedirect

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.
 
 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  *     (http://www.torchmobile.com/)
  *
@@ skipping 1222 matching lines @@
   DCHECK(entry);
 
   // The URL may have changed due to redirects.
   entry->set_page_type(params.url_is_unreachable ? PAGE_TYPE_ERROR
                                                  : PAGE_TYPE_NORMAL);
   entry->SetURL(params.url);
   entry->SetReferrer(params.referrer);
   if (entry->update_virtual_url_with_url())
     UpdateVirtualURLToURL(entry, params.url);
 
-  // The site instance will normally be the same except during session restore,
-  // when no site instance will be assigned.
+  // The site instance will normally be the same except
+  // 1) session restore, when no site instance will be assigned or
+  // 2) redirect, when the site instance is reset.
   DCHECK(entry->site_instance() == nullptr ||
+         !entry->GetRedirectChain().empty() ||
          entry->site_instance() == rfh->GetSiteInstance());
 
   // Update the existing FrameNavigationEntry to ensure all of its members
   // reflect the parameters coming from the renderer process.
   entry->AddOrUpdateFrameEntry(
       rfh->frame_tree_node(), params.item_sequence_number,
       params.document_sequence_number, rfh->GetSiteInstance(), nullptr,
       params.url, params.referrer, params.redirects, params.page_state,
       params.method, params.post_id);
 
@@ skipping 897 matching lines @@
     }
   }
 }
 
 void NavigationControllerImpl::SetGetTimestampCallbackForTest(
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 }  // namespace content