Fix DetachableResourceHandler when OnResponseCompleted is deferred.

content/browser/loader/detachable_resource_handler.cc

Index: content/browser/loader/detachable_resource_handler.cc
diff --git a/content/browser/loader/detachable_resource_handler.cc b/content/browser/loader/detachable_resource_handler.cc
index 85ac2d386069f9223dd693156624c04b662379ea..15ab8c3adf98798b3c74a306825bf22f7f1fb134 100644
--- a/content/browser/loader/detachable_resource_handler.cc
+++ b/content/browser/loader/detachable_resource_handler.cc
@@ -226,7 +226,9 @@ void DetachableResourceHandler::OnResponseCompleted(
 
   is_finished_ = true;
 
-  next_handler_->OnResponseCompleted(status, std::move(controller));
+  HoldController(std::move(controller));
+  next_handler_->OnResponseCompleted(status,
+                                     base::MakeUnique<Controller>(this));
 }
 
 void DetachableResourceHandler::OnDataDownloaded(int bytes_downloaded) {