Fix and refactor downloaded file handling in the loading stack

content/browser/loader/mojo_async_resource_handler.cc

Index: content/browser/loader/mojo_async_resource_handler.cc
diff --git a/content/browser/loader/mojo_async_resource_handler.cc b/content/browser/loader/mojo_async_resource_handler.cc
index 6d5a9d7c4a08f396856ebee72852a861a6a3eb21..9781b8c5289d5f35d80d448df80f022d3f3cf4f0 100644
--- a/content/browser/loader/mojo_async_resource_handler.cc
+++ b/content/browser/loader/mojo_async_resource_handler.cc
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/time/time.h"
+#include "content/browser/loader/downloaded_temp_file_impl.h"
 #include "content/browser/loader/netlog_observer.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_request_info_impl.h"
@@ -145,7 +146,18 @@ bool MojoAsyncResourceHandler::OnResponseStarted(ResourceResponse* response,
   response->head.request_start = request()->creation_time();
   response->head.response_start = base::TimeTicks::Now();
   sent_received_response_message_ = true;
-  url_loader_client_->OnReceiveResponse(response->head);
+
+  mojom::DownloadedTempFilePtr downloaded_file_ptr;
+  if (!response->head.download_file_path.empty()) {
+    auto downloaded_file = base::MakeUnique<DownloadedTempFileImpl>(
+        rdh_, info->GetChildID(), info->GetRequestID(),
+        response->head.download_file_path);
+    downloaded_file_ptr = downloaded_file->CreateInterfacePtrAndBind();
+    rdh_->RegisterDownloadedTempFile(std::move(downloaded_file));
+  }
+
+  url_loader_client_->OnReceiveResponse(response->head,
+                                        std::move(downloaded_file_ptr));
   return true;
 }