### 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
void FramelessView::ResetWindowControls() {}
void FramelessView::UpdateWindowIcon() {}
void FramelessView::UpdateWindowTitle() {}
void FramelessView::SizeConstraintsChanged() {}
gfx::Size FramelessView::CalculatePreferredSize() const {
  return frame_->non_client_view()
      ->GetWindowBoundsForClientBounds(
          gfx::Rect(frame_->client_view()->GetPreferredSize()))
      .size();
}
gfx::Size FramelessView::GetMinimumSize() const {
  return window_->GetContentMinimumSize();
}
gfx::Size FramelessView::GetMaximumSize() const {
  return window_->GetContentMaximumSize();
}
const char* FramelessView::GetClassName() const {
  return kViewClassName;
}
}