Allow asynchronous deferral in NavigationSimulator

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index 2e525bbe4956a473d0c41d0d2051e1d5801bdef4..ade978785d2142c4dafcd6b49164b00dccb26fa4 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -872,6 +872,11 @@ void NavigationHandleImpl::RunCompleteCallback(
   ThrottleChecksFinishedCallback callback = complete_callback_;
   complete_callback_.Reset();
 
+  if (!complete_callback_for_testing_.is_null()) {
+    complete_callback_for_testing_.Run(result);
+    complete_callback_for_testing_.Reset();
+  }
+
   if (!callback.is_null())
     callback.Run(result);