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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
const content::Referrer& referrer,
                       const std::string& frame_name,
                       WindowOpenDisposition disposition,
                       const blink::mojom::WindowFeatures& features,
                       const std::vector<std::string>& additional_features,
                       const scoped_refptr<network::ResourceRequestBody>& body,
                       bool user_gesture,
                       bool opener_suppressed,
                       bool* no_javascript_access) override;
#if BUILDFLAG(ENABLE_PICTURE_IN_PICTURE)
  std::unique_ptr<content::OverlayWindow> CreateWindowForPictureInPicture(
      content::PictureInPictureWindowController* controller) override;
#endif
  void GetAdditionalAllowedSchemesForFileSystem(
      std::vector<std::string>* additional_schemes) override;
  void GetAdditionalWebUISchemes(
      std::vector<std::string>* additional_schemes) override;
  void SiteInstanceDeleting(content::SiteInstance* site_instance) override;
  std::unique_ptr<net::ClientCertStore> CreateClientCertStore(
      content::BrowserContext* browser_context) override;
  std::unique_ptr<device::LocationProvider> OverrideSystemLocationProvider()
      override;
  mojo::Remote<network::mojom::NetworkContext> CreateNetworkContext(
      content::BrowserContext* browser_context,
      bool in_memory,
      const base::FilePath& relative_partition_path) override;
  network::mojom::NetworkContext* GetSystemNetworkContext() override;
  base::Optional<service_manager::Manifest> GetServiceManifestOverlay(
      base::StringPiece name) override;
  content::MediaObserver* GetMediaObserver() override;