Got disabled in chromium 71 upgrade https://github.com/electron/electron/commit/798b2a3ffd55c477af6258f0afb71000c9f8ecde

/cc @brenca @codebytere 
atom/browser/osr/osr_render_widget_host_view.cc
damage.Union(rect);
      canvas.writePixels(*popup_bitmap_.get(), origin_in_pixels.x(),
                         origin_in_pixels.y());
    }
    for (auto* proxy_view : proxy_views_) {
      gfx::Rect rect = proxy_view->GetBounds();
      gfx::Point origin_in_pixels =
          gfx::ConvertPointToPixel(current_device_scale_factor_, rect.origin());
      damage.Union(rect);
      canvas.writePixels(*proxy_view->GetBitmap(), origin_in_pixels.x(),
                         origin_in_pixels.y());
    }
    damage.Intersect(GetViewBounds());
    paint_callback_running_ = true;
    callback_.Run(damage, backing);
    paint_callback_running_ = false;
  }
  ReleaseResize();
}
void OffScreenRenderWidgetHostView::OnPopupPaint(const gfx::Rect& damage_rect,
                                                 const SkBitmap& bitmap) {
  if (popup_host_view_ && popup_bitmap_.get())
    popup_bitmap_.reset(new SkBitmap(bitmap));
  InvalidateBounds(popup_host_view_->popup_position_);
}
void OffScreenRenderWidgetHostView::OnProxyViewPaint(
    const gfx::Rect& damage_rect) {
  InvalidateBounds(damage_rect);
}
void OffScreenRenderWidgetHostView::HoldResize() {