### 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/ui/views/frameless_view.cc
return bounds();
}
gfx::Rect FramelessView::GetWindowBoundsForClientBounds(
    const gfx::Rect& client_bounds) const {
  gfx::Rect window_bounds = client_bounds;
  
  
  
  if (window_bounds.IsEmpty()) {
    window_bounds.set_width(1);
    window_bounds.set_height(1);
  }
  return window_bounds;
}
int FramelessView::NonClientHitTest(const gfx::Point& cursor) {
  if (frame_->IsFullscreen())
    return HTCLIENT;
  
  
  SkRegion* draggable_region = window_->draggable_region();
  if (draggable_region && draggable_region->contains(cursor.x(), cursor.y()))
    return HTCAPTION;
  
  int frame_component = ResizingBorderHitTest(cursor);
  if (frame_component != HTNOWHERE)
    return frame_component;
  return HTCLIENT;
}
void FramelessView::GetWindowMask(const gfx::Size& size, SkPath* window_mask) {}