### Issue Details
in frameless windows 
While setting browserview style to draggable by webkit-app-region : drag. the area won't be draggable after that
and it can not move main window 
### Electron Version:
11.0.1
### Operating System:
Windows 10 (1803)
Last Known Working Electron version:
not found
### Expected Behavior
Browser view moves the main window while I set the style of the body or one of the area to
-webkit-app-region: drag;

### Actual Behavior
nothing happen in browserview after styling -webkit-app-region: drag;

I know it is mention that in 11 version it is fixed. but it still dosn't work 

### To Reproduce
https://gist.github.com/pejmanpesyan/8540aad65e7c6980c45f23e5eaafafb9

shell/browser/native_browser_view_views.h
public:
  explicit NativeBrowserViewViews(
      InspectableWebContents* inspectable_web_contents);
  ~NativeBrowserViewViews() override;
  void SetAutoResizeProportions(const gfx::Size& window_size);
  void AutoResize(const gfx::Rect& new_window,
                  int width_delta,
                  int height_delta);
  uint8_t GetAutoResizeFlags() { return auto_resize_flags_; }
  
  void SetAutoResizeFlags(uint8_t flags) override;
  void SetBounds(const gfx::Rect& bounds) override;
  gfx::Rect GetBounds() override;
  void SetBackgroundColor(SkColor color) override;
 private:
  void ResetAutoResizeProportions();
  uint8_t auto_resize_flags_ = 0;
  bool auto_horizontal_proportion_set_ = false;
  float auto_horizontal_proportion_width_ = 0.;
  float auto_horizontal_proportion_left_ = 0.;
  bool auto_vertical_proportion_set_ = false;
  float auto_vertical_proportion_height_ = 0.;
  float auto_vertical_proportion_top_ = 0.;
  DISALLOW_COPY_AND_ASSIGN(NativeBrowserViewViews);
};
}  
#endif