[NoStatePrefetch] Do not send responses to renderer in prefetch mode.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 7c13c18e19f3cca5553b8681b09ff77650559056..2bb52ebb117af321996b4fa86279a14f26d94eb7 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -4068,6 +4068,11 @@ void RenderFrameImpl::willSendRequest(
       navigation_state->start_params().transferred_request_request_id);
   extra_data->set_service_worker_provider_id(provider_id);
   extra_data->set_stream_override(std::move(stream_override));
+  bool is_prefetch = frame->document().isPrefetchOnly();
+  extra_data->set_is_prefetch(is_prefetch);
+  extra_data->set_download_to_network_cache_only(
+      is_prefetch &&
+      WebURLRequestToResourceType(request) != RESOURCE_TYPE_MAIN_FRAME);
   WebString error;
   extra_data->set_initiated_in_secure_context(
       frame->document().isSecureContext(error));