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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
v8::Isolate* isolate_;
  v8::Global<v8::Function> body_func_;
};
gin::WrapperInfo JSChunkedDataPipeGetter::kWrapperInfo = {
    gin::kEmbedderNativeGin};
const net::NetworkTrafficAnnotationTag kTrafficAnnotation =
    net::DefineNetworkTrafficAnnotation("electron_net_module", R"(
        semantics {
          sender: "Electron Net module"
          description:
            "Issue HTTP/HTTPS requests using Chromium's native networking "
            "library."
          trigger: "Using the Net module"
          data: "Anything the user wants to send."
          destination: OTHER
        }
        policy {
          cookies_allowed: YES
          cookies_store: "user"
          setting: "This feature cannot be disabled."
        })");
base::IDMap<SimpleURLLoaderWrapper*>& GetAllRequests() {
  static base::NoDestructor<base::IDMap<SimpleURLLoaderWrapper*>>
      s_all_requests;
  return *s_all_requests;
}
}  
gin::WrapperInfo SimpleURLLoaderWrapper::kWrapperInfo = {
    gin::kEmbedderNativeGin};
SimpleURLLoaderWrapper::SimpleURLLoaderWrapper(