<!--  As an open source project with a dedicated but small maintainer team, it can sometimes take a long time for issues to be addressed so please be patient and we will get back to you as soon as we can.
-->

### Preflight Checklist
<!-- Please ensure you've completed the following steps by replacing [ ] with [x]-->

* [x] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
* [x] I have searched the issue tracker for an issue that matches the one I want to file, without success.

### Issue Details

* **Electron Version:**
  * <!-- (output of `node_modules/.bin/electron --version`) e.g. 4.0.3 -->9.2.0
* **Operating System:**
  * <!-- (Platform and Version) e.g. macOS 10.13.6 / Windows 10 (1803) / Ubuntu 18.04 x64 -->win10
* **Last Known Working Electron version:**
  * <!-- (if applicable) e.g. 3.1.0 -->

### Expected Behavior
[this is config](https://www.electronjs.org/docs/api/web-contents#contentsprintoptions-callback)
<!-- A clear and concise description of what you expected to happen. -->The saved PDF has a custom `header`, and the `pageRanges` is work.

### Actual Behavior
<!-- A clear and concise description of what actually happened. -->
`header` and `pageRanges` is not work.
### To Reproduce
<!--
Your best chance of getting this bug looked at quickly is to provide an example.
-->

<!--
For bugs that can be encapsulated in a small experiment, you can use Electron Fiddle (https://github.com/electron/fiddle) to publish your example to a GitHub Gist and link it your bug report.
-->
[my electron fiddle](https://gist.github.com/36d96e2fe459dab8ffed2a764d751528)
<!--
If Fiddle is insufficient to produce an example, please provide an example REPOSITORY that can be cloned and run. You can fork electron-quick-start (https://github.com/electron/electron-quick-start) and include a link to the branch with your changes.
-->

<!--
If you provide a URL, please list the commands required to clone/setup/run your repo e.g.
```sh
$ git clone $YOUR_URL -b $BRANCH
$ npm install
$ npm start || electron .
```
-->

### Screenshots
<!-- If applicable, add screenshots to help explain your problem. -->
![image](https://user-images.githubusercontent.com/19225429/90504323-7d74e680-e183-11ea-86df-6f6925e77616.png)


### Additional Information
<!-- Add any other context about the problem here. -->
Finally, who can tell me how to determine the total number of pages generated by the printer system of Chrome?

shell/browser/api/electron_api_web_contents.cc
const std::string& webrtc_ip_handling_policy) {
  if (GetWebRTCIPHandlingPolicy() == webrtc_ip_handling_policy)
    return;
  ontents()->GetMutableRendererPrefs()->webrtc_ip_handling_policy =
      webrtc_ip_handling_policy;
  ontents()->SyncRendererPrefs();
}
bool WebContents::IsCrashed() const {
  return ontents()->IsCrashed();
}
void WebContents::SetUserAgent(const std::string& user_agent) {
  ontents()->SetUserAgentOverride(
      blink::UserAgentOverride::UserAgentOnly(user_agent), false);
}
std::string WebContents::GetUserAgent() {
  return ontents()->GetUserAgentOverride().ua_string_override;
}
v8::Local<v8::Promise> WebContents::SavePage(
    const base::FilePath& full_file_path,
    const content::SavePageType& save_type) {
  v8::Isolate* isolate = JavascriptEnvironment::GetIsolate();
  gin_helper::Promise<void> promise(isolate);
  v8::Local<v8::Promise> handle = promise.GetHandle();
  auto* handler = new SavePageHandler(ontents(), std::move(promise));
  handler->Handle(full_file_path, save_type);
  return handle;
}
void WebContents::OpenDevTools(gin::Arguments* args) {