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### Issue Details

* **Electron Version:**
  * Tested with 8.0.0 and v9.0.0-beta.1
* **Operating System:**
  * macOS 10.15.3 (19D76)
* **Last Known Working Electron version:**
  * 7.1.12

### Expected Behavior

`navigator.mediaDevices.enumerateDevices()` should return a list of MediaDevices with a `label` and a `deviceId` property. The `deviceId` property should stay the same across reloads and restarts.

### Actual Behavior
The `deviceId` property changes with every reload/restart.

### To Reproduce
Simply execute `navigator.mediaDevices.enumerateDevices()` in the renderer process and compare the ids of the media devices to a different execution.

See this fork for an example:
https://github.com/codedrift/electron-quick-start

```sh
$ git clone https://github.com/codedrift/electron-quick-start -b media-device-ids
$ npm install
$ npm start || electron .
```

### Additional Information
It seems to work fine in a regular Chrome 80 browser. 

shell/browser/electron_browser_client.h
content::RenderFrameHost* render_frame_host,
      content::SiteInstance* pending_site_instance) override;
  void AppendExtraCommandLineSwitches(base::CommandLine* command_line,
                                      int child_process_id) override;
  void DidCreatePpapiPlugin(content::BrowserPpapiHost* browser_host) override;
  std::string GetGeolocationApiKey() override;
  scoped_refptr<content::QuotaPermissionContext> CreateQuotaPermissionContext()
      override;
  content::GeneratedCodeCacheSettings GetGeneratedCodeCacheSettings(
      content::BrowserContext* context) override;
  void AllowCertificateError(
      content::WebContents* web_contents,
      int cert_error,
      const net::SSLInfo& ssl_info,
      const GURL& request_url,
      bool is_main_frame_request,
      bool strict_enforcement,
      base::OnceCallback<void(content::CertificateRequestResultType)> callback)
      override;
  base::OnceClosure SelectClientCertificate(
      content::WebContents* web_contents,
      net::SSLCertRequestInfo* cert_request_info,
      net::ClientCertIdentityList client_certs,
      std::unique_ptr<content::ClientCertificateDelegate> delegate) override;
  bool CanCreateWindow(content::RenderFrameHost* opener,
                       const GURL& opener_url,
                       const GURL& opener_top_level_frame_url,
                       const url::Origin& source_origin,
                       content::mojom::WindowContainerType container_type,
                       const GURL& target_url,