* Electron Version: 3.0.0-beta1
* Operating System (Platform and Version): macOS
* Last known working Electron version: 2.0.2

**Expected Behavior**
```css
html, body, * {
    -webkit-app-region: drag;
    -webkit-user-select: none;
    cursor: default;
}
```
should allow users to move the position of the window by dragging it directly.

**Actual behavior**
The window is not draggable.
The `cursor` and `-webkit-user-select` properties work well.

**To Reproduce**
copy the CSS above, paste it into a frameless app's `<style>` tag, and run the app.

**Screenshots**

**Additional Information**

atom/browser/native_window_mac.h
NORMAL,
    HIDDEN,
    HIDDEN_INSET,
    CUSTOM_BUTTONS_ON_HOVER,
  };
  TitleBarStyle title_bar_style() const { return title_bar_style_; }
  AtomPreviewItem* preview_item() const { return preview_item_.get(); }
  AtomTouchBar* touch_bar() const { return touch_bar_.get(); }
  bool zoom_to_page_width() const { return zoom_to_page_width_; }
  bool fullscreen_window_title() const { return fullscreen_window_title_; }
  bool simple_fullscreen() const { return always_simple_fullscreen_; }
 protected:
  
  bool CanResize() const override;
  views::View* GetContentsView() override;
 private:
  void InternalSetParentWindow(NativeWindow* parent, bool attach);
  void ShowWindowButton(NSWindowButton button);
  void SetForwardMouseMessages(bool forward);
  AtomNSWindow* window_;  
  base::scoped_nsobject<AtomNSWindowDelegate> window_delegate_;
  base::scoped_nsobject<AtomPreviewItem> preview_item_;
  base::scoped_nsobject<AtomTouchBar> touch_bar_;
  base::scoped_nsobject<CustomWindowButtonView> buttons_view_;
  
  id wheel_event_monitor_;