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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
int child_id,
      content::NavigationUIData* navigation_data,
      bool is_main_frame,
      ui::PageTransition page_transition,
      bool has_user_gesture,
      const base::Optional<url::Origin>& initiating_origin,
      mojo::PendingRemote<network::mojom::URLLoaderFactory>* out_factory)
      override;
  std::unique_ptr<content::LoginDelegate> CreateLoginDelegate(
      const net::AuthChallengeInfo& auth_info,
      content::WebContents* web_contents,
      const content::GlobalRequestID& request_id,
      bool is_main_frame,
      const GURL& url,
      scoped_refptr<net::HttpResponseHeaders> response_headers,
      bool first_auth_attempt,
      LoginAuthRequiredCallback auth_required_callback) override;
  void SiteInstanceGotProcess(content::SiteInstance* site_instance) override;
  std::vector<std::unique_ptr<blink::URLLoaderThrottle>>
  CreateURLLoaderThrottles(
      const network::ResourceRequest& request,
      content::BrowserContext* browser_context,
      const base::RepeatingCallback<content::WebContents*()>& wc_getter,
      content::NavigationUIData* navigation_ui_data,
      int frame_tree_node_id) override;
  base::flat_set<std::string> GetPluginMimeTypesWithExternalHandlers(
      content::BrowserContext* browser_context) override;
  bool IsSuitableHost(content::RenderProcessHost* process_host,
                      const GURL& site_url) override;
  bool ShouldUseProcessPerSite(content::BrowserContext* browser_context,