Fix the current per-frame URLLoaderFactory code path.

content/child/web_url_loader_impl.cc

Index: content/child/web_url_loader_impl.cc
diff --git a/content/child/web_url_loader_impl.cc b/content/child/web_url_loader_impl.cc
index 851c68c5b2e80489aab4624a6663c03f3ccc746d..0bf318d3cacc71ce9ba818d92404f22560203b21 100644
--- a/content/child/web_url_loader_impl.cc
+++ b/content/child/web_url_loader_impl.cc
@@ -634,6 +634,8 @@ void WebURLLoaderImpl::Context::Start(const WebURLRequest& request,
   else
     extra_data = &empty_extra_data;
   extra_data->CopyToResourceRequest(resource_request.get());
+  if (extra_data->url_loader_factory_override())
+    url_loader_factory_ = extra_data->url_loader_factory_override();
 
   if (sync_load_response) {
     DCHECK(defers_loading_ == NOT_DEFERRING);