Fix NavigationControllerBrowserTest.SubframeForwardRedirect

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 5bde4bb4340d76cb67cc37f410824c5a814269d9..06c2fb1b842c81b2adfd6252403ef78fcf7ce4b6 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -1240,9 +1240,11 @@ void NavigationControllerImpl::RendererDidNavigateToExistingPage(
   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