Refactoring DownloadManager::DownloadURL to add proper annotation.

chrome/browser/extensions/api/streams_private/streams_private_apitest.cc

Index: chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
diff --git a/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc b/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
index 40c094a52ab78fe7207b0cf6f2d6ca561dd4266e..dac19715b8abdee17e75d909551bdc538cb3b7a1 100644
--- a/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
+++ b/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
@@ -30,6 +30,7 @@
 #include "net/test/embedded_test_server/embedded_test_server.h"
 #include "net/test/embedded_test_server/http_request.h"
 #include "net/test/embedded_test_server/http_response.h"
+#include "net/traffic_annotation/network_traffic_annotation_test_helper.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 using content::BrowserContext;
@@ -390,7 +391,8 @@ IN_PROC_BROWSER_TEST_F(StreamsPrivateApiTest, DirectDownload) {
   params->set_file_path(target_path);
 
   // Start download of the URL with a path "/text_path.txt" on the test server.
-  download_manager->DownloadUrl(std::move(params));
+  download_manager->DownloadUrl(std::move(params),
+                                TRAFFIC_ANNOTATION_FOR_TESTS);
 
   // Wait for the download to start.
   download_observer->WaitForFinished();