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### Preflight Checklist
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* [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 a feature request that matches the one I want to file, without success.

### Problem Description
<!-- Is your feature request related to a problem? Please add a clear and concise description of what the problem is. -->

Hi, I'm trying to integrate uBlock Origin extension into my app, using my own package [electron-extensions](https://github.com/sentialx/electron-extensions). But I can see uBlock Origin uses `chrome.tabs.insertCSS` with `cssOrigin` set to `user`. The property is important to block elements with `display: block !important`.

### Proposed Solution
<!-- Describe the solution you'd like in a clear and concise manner -->
In `webContents.insertCSS` there should be a `details` object with at least `cssOrigin` property as it's described [here](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/insertCSS).

### Alternatives Considered
Unfortunately there are no alternatives. If there were any, I wouldn't create this issue.

shell/renderer/api/atom_api_web_frame.cc
args->GetNext(&scriptExecutionType);
  
  
  
  GetRenderFrame(window)->GetWebFrame()->RequestExecuteScriptInIsolatedWorld(
      world_id, &sources.front(), sources.size(), has_user_gesture,
      scriptExecutionType, new ScriptExecutionCallback(std::move(promise)));
  return handle;
}
void SetIsolatedWorldInfo(v8::Local<v8::Value> window,
                          int world_id,
                          const mate::Dictionary& options,
                          mate::Arguments* args) {
  std::string origin_url, security_policy, name;
  options.Get("securityOrigin", &origin_url);
  options.Get("csp", &security_policy);
  options.Get("name", &name);
  if (!security_policy.empty() && origin_url.empty()) {
    args->ThrowError(
        "If csp is specified, securityOrigin should also be specified");
    return;
  }
  blink::WebIsolatedWorldInfo info;
  info.security_origin = blink::WebSecurityOrigin::CreateFromString(
      blink::WebString::FromUTF8(origin_url));
  info.content_security_policy = blink::WebString::FromUTF8(security_policy);
  info.human_readable_name = blink::WebString::FromUTF8(name);
  GetRenderFrame(window)->GetWebFrame()->SetIsolatedWorldInfo(world_id, info);
}
blink::WebCache::ResourceTypeStats GetResourceUsage(v8::Isolate* isolate) {