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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.cc
content::SiteInstance* site_instance,
                   const GURL& dest_url) {
  return site_instance->IsSameSiteWithURL(dest_url) ||
         
         
         
         (content::SiteInstance::GetSiteForURL(browser_context, dest_url) ==
          site_instance->GetSiteURL());
}
ElectronBrowserClient* g_browser_client = nullptr;
base::LazyInstance<std::string>::DestructorAtExit
    g_io_thread_application_locale = LAZY_INSTANCE_INITIALIZER;
base::NoDestructor<std::string> g_application_locale;
void SetApplicationLocaleOnIOThread(const std::string& locale) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);
  g_io_thread_application_locale.Get() = locale;
}
void BindNetworkHintsHandler(
    content::RenderFrameHost* frame_host,
    mojo::PendingReceiver<network_hints::mojom::NetworkHintsHandler> receiver) {
  NetworkHintsHandlerImpl::Create(frame_host, std::move(receiver));
}
#if defined(OS_WIN)
const base::FilePath::StringPieceType kPathDelimiter = FILE_PATH_LITERAL(";");
#else
const base::FilePath::StringPieceType kPathDelimiter = FILE_PATH_LITERAL(":");
#endif
#if BUILDFLAG(ENABLE_ELECTRON_EXTENSIONS)
enum RenderProcessHostPrivilege {