Fix NavigationControllerBrowserTest.SubframeForwardRedirect

content/browser/frame_host/navigation_request.cc

Index: content/browser/frame_host/navigation_request.cc
diff --git a/content/browser/frame_host/navigation_request.cc b/content/browser/frame_host/navigation_request.cc
index 2c04eda2a0049f3e5b9213d0edae444f6add6b2b..5d0c5bb669a37c6749c8fd85c33dbcca61a18f5d 100644
--- a/content/browser/frame_host/navigation_request.cc
+++ b/content/browser/frame_host/navigation_request.cc
@@ -388,6 +388,10 @@ void NavigationRequest::TransferNavigationHandleOwnership(
 void NavigationRequest::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     const scoped_refptr<ResourceResponse>& response) {
+  // If a redirect occurs, the original site instance we thought is the
+  // destination could change.
+  dest_site_instance_ = nullptr;
+
   // If the navigation is no longer a POST, the POST data should be reset.
   if (redirect_info.new_method != "POST")
     common_params_.post_data = nullptr;