Bring back the URLLoader from the old Mandoline network service.

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index 0a43bbcc8915cc07648bceb06f40dd1cad47f776..460bb75c58323470df5200319c4958575b8869fd 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -1389,6 +1389,7 @@ test("content_unittests") {
     "../common/service_manager/service_manager_connection_impl_unittest.cc",
     "../common/service_worker/service_worker_utils_unittest.cc",
     "../common/webplugininfo_unittest.cc",
+    "../network/url_loader_unittest.cc",
     "../public/test/referrer_unittest.cc",
     "../renderer/android/disambiguation_popup_helper_unittest.cc",
     "../renderer/bmp_image_decoder_unittest.cc",
@@ -1483,6 +1484,7 @@ test("content_unittests") {
     "//content/browser/speech/proto",
     "//content/child:for_content_tests",
     "//content/gpu",
+    "//content/network",
     "//content/public/browser",
     "//content/public/child",
     "//content/public/common",