### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

v14.0.0-nightly.20210426

### What operating system are you using?

Windows

### Operating System Version

Windows 10

### What arch are you using?

x64

### Last Known Working Electron version

v14.0.0-nightly.20210413

### Expected Behavior

`BrowserViews` load their `webContents`

### Actual Behavior

BrowserViews will not load `webContents` properly.

### Testcase Gist URL

https://gist.github.com/712a2fde2757736c9dbf6c3e7e0aa18b

### Additional Information

Bisected range: https://github.com/electron/electron/compare/v14.0.0-nightly.20210413...v14.0.0-nightly.20210426
shell/browser/ui/views/inspectable_web_contents_view_views.h
class Widget;
class WidgetDelegate;
}  
namespace electron {
class InspectableWebContents;
class InspectableWebContentsViewViews : public InspectableWebContentsView,
                                        public views::View {
 public:
  explicit InspectableWebContentsViewViews(
      InspectableWebContents* inspectable_web_contents);
  ~InspectableWebContentsViewViews() override;
  
  views::View* GetView() override;
  views::View* GetWebView() override;
  void ShowDevTools(bool activate) override;
  void CloseDevTools() override;
  bool IsDevToolsViewShowing() override;
  bool IsDevToolsViewFocused() override;
  void SetIsDocked(bool docked, bool activate) override;
  void SetContentsResizingStrategy(
      const DevToolsContentsResizingStrategy& strategy) override;
  void SetTitle(const std::u16string& title) override;
  InspectableWebContents* inspectable_web_contents() {