<!--  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: All Version
Operating System: macOS 10.15.3
Last Known Working Electron version: Never

### Bug
The color picker in devtools does not work.
In devtools if you want to change the colors of the CSS code. When you click on a color a color picker is supposed to appear but it does not appear.

### Screenshots
<img width="1013" alt="Capture d’écran 2020-09-07 à 11 42 44" src="https://user-images.githubusercontent.com/70572698/92374841-988ea280-f100-11ea-96be-afc93f6dd645.png">

shell/browser/api/electron_api_web_contents.cc
gin::HContents> WebContents::CreateFromWebPreferences(
    v8::Isolate* isolate,
    const gin_helper::Dictionary& web_preferences) {
   Check if webPreferences has |webContents| option.
  gin::HContents> ontents;
  if (web_preferences.GetHidden("webContents", &ontents) &&
      !ontents.IsEmpty()) {
     Set webPreferences from options if using an existing webContents.
     These preferences will be used when the webContent launches new
     render processes.
    auto* existing_preferences =
        WebContentsPreferences::From(ontents->ontents());
    base::DictionaryValue web_preferences_dict;
    if (gin::ConvertFromV8(isolate, web_preferences.GetHandle(),
                           &web_preferences_dict)) {
      existing_preferences->Clear();
      existing_preferences->Merge(web_preferences_dict);
    }
  } else {
     Create one if not.
    ontents = WebContents::New(isolate, web_preferences);
  }
  return ontents;
}
 static