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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::DevToolsManagerDelegate* GetDevToolsManagerDelegate() override;
  content::PlatformNotificationService* GetPlatformNotificationService(
      content::BrowserContext* browser_context) override;
  std::unique_ptr<content::BrowserMainParts> CreateBrowserMainParts(
      const content::MainFunctionParams&) override;
  base::FilePath GetDefaultDownloadDirectory() override;
  scoped_refptr<network::SharedURLLoaderFactory>
  GetSystemSharedURLLoaderFactory() override;
  void OnNetworkServiceCreated(
      network::mojom::NetworkService* network_service) override;
  std::vector<base::FilePath> GetNetworkContextsParentDirectory() override;
  std::string GetProduct() override;
  void RegisterNonNetworkNavigationURLLoaderFactories(
      int frame_tree_node_id,
      NonNetworkURLLoaderFactoryMap* factories) override;
  void RegisterNonNetworkSubresourceURLLoaderFactories(
      int render_process_id,
      int render_frame_id,
      NonNetworkURLLoaderFactoryMap* factories) override;
  void CreateWebSocket(
      content::RenderFrameHost* frame,
      WebSocketFactory factory,
      const GURL& url,
      const net::SiteForCookies& site_for_cookies,
      const base::Optional<std::string>& user_agent,
      mojo::PendingRemote<network::mojom::WebSocketHandshakeClient>
          handshake_client) override;
  bool WillInterceptWebSocket(content::RenderFrameHost*) override;
  bool WillCreateURLLoaderFactory(
      content::BrowserContext* browser_context,