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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::Isolate::GetCurrent();
  pinned_wrapper_.Reset(isolate, GetWrapper(isolate).ToLocalChecked());
}
void SimpleURLLoaderWrapper::PinBodyGetter(v8::Local<v8::Value> body_getter) {
  pinned_chunk_pipe_getter_.Reset(v8::Isolate::GetCurrent(), body_getter);
}
SimpleURLLoaderWrapper::~SimpleURLLoaderWrapper() {
  GetAllRequests().Remove(id_);
}
SimpleURLLoaderWrapper* SimpleURLLoaderWrapper::FromID(uint32_t id) {
  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
  return GetAllRequests().Lookup(id);
}
void SimpleURLLoaderWrapper::OnAuthRequired(