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### Issue Details

* **Electron Version:**
  8.0.1
* **Operating System:**
  macOS 10.14.6

### Expected Behavior
Send a request with `referer` header. It's worked with Node's `http/https` module, but failed when I change to `net.request`.

### Actual Behavior
No referer header

### To Reproduce
```js
ses.protocol.interceptStreamProtocol("https", (request, callback) => {
	const resp = sendRequestWithNetRequest({
       url: request.url,
       method: request.method,
	   headers: {
			...request.headers,
			referer: request.referrer  // only referrer has been ignored!!
       }
    })
    callback({
        data: resp.body,
        statusCode: resp.statusCode,
        headers: resp.headers
      });
});
```

shell/browser/api/electron_api_url_loader.cc
loader_.reset();
  pinned_wrapper_.Reset();
  pinned_chunk_pipe_getter_.Reset();
  
  
}
gin::Handle<SimpleURLLoaderWrapper> SimpleURLLoaderWrapper::Create(
    gin::Arguments* args) {
  gin_helper::Dictionary opts;
  if (!args->GetNext(&opts)) {
    args->ThrowTypeError("Expected a dictionary");
    return gin::Handle<SimpleURLLoaderWrapper>();
  }
  auto request = std::make_unique<network::ResourceRequest>();
  request->force_ignore_site_for_cookies = true;
  opts.Get("method", &request->method);
  opts.Get("url", &request->url);
  std::map<std::string, std::string> extra_headers;
  if (opts.Get("extraHeaders", &extra_headers)) {
    for (const auto& it : extra_headers) {
      if (!net::HttpUtil::IsValidHeaderName(it.first) ||
          !net::HttpUtil::IsValidHeaderValue(it.second)) {
        args->ThrowTypeError("Invalid header name or value");
        return gin::Handle<SimpleURLLoaderWrapper>();
      }
      request->headers.SetHeader(it.first, it.second);
    }