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### Issue Details
This is a bug report specifically for the 7.0 beta. 

* **Electron Version:**
  * 7.0.0-beta.6
* **Operating System:**
  * Ubuntu 18.04 x64, Windows 10
* **Last Known Working Electron version:**
  * 6.0.12

### Expected Behavior
SharedWorker should be functional and *shared* when using
  a custom protocol to provide a proper origin.

### Actual Behavior
SharedWorker does not execute when loaded from custom protocol.
It does execute when page is loaded with the `file://` protocol, but this 
  defeats the purpose, since it is not shared between contexts.

Also noticed while diagnosing the issue:
Creating a SharedWorker with node integration enabled using a Data URL crashes 
the renderer.  I verified that this works in Electron 6, figured the cause might be related.

### To Reproduce
Install and run the following repo:

https://github.com/krisdages/electron-7-shared-worker-broken

$ git clone https://github.com/krisdages/electron-7-shared-worker-broken
$ npm install
$ npm start

Sorry, had it implemented before seeing the "electron fiddle" option. May try that next time.

Thanks for looking into this :)
shell/browser/electron_browser_client.cc
ElectronBrowserClient::GetServiceManifestOverlay(base::StringPiece name) {
  if (name == content::mojom::kBrowserServiceName)
    return GetElectronContentBrowserOverlayManifest();
  return base::nullopt;
}
std::unique_ptr<content::BrowserMainParts>
ElectronBrowserClient::CreateBrowserMainParts(
    const content::MainFunctionParams& params) {
  return std::make_unique<ElectronBrowserMainParts>(params);
}
void ElectronBrowserClient::WebNotificationAllowed(
    int render_process_id,
    base::OnceCallback<void(bool, bool)> callback) {
  content::WebContents* web_contents =
      WebContentsPreferences::GetWebContentsFromProcessID(render_process_id);
  if (!web_contents) {
    std::move(callback).Run(false, false);
    return;
  }
  auto* permission_helper =
      WebContentsPermissionHelper::FromWebContents(web_contents);
  if (!permission_helper) {
    std::move(callback).Run(false, false);
    return;
  }
  permission_helper->RequestWebNotificationPermission(
      base::BindOnce(std::move(callback), web_contents->IsAudioMuted()));
}
void ElectronBrowserClient::RenderProcessHostDestroyed(