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
if (transparent_) {
    SetBackgroundColor(SkColor());
#if defined(OS_MACOSX)
    browser_compositor_->SetBackgroundColor(SK_ColorTRANSPARENT);
#else
    compositor_->SetBackgroundColor(SK_ColorTRANSPARENT);
#endif
    return true;
  }
  return false;
}
void OffScreenRenderWidgetHostView::SetNeedsBeginFrames(
    bool needs_begin_frames) {
  SetupFrameRate(true);
  begin_frame_timer_->SetActive(needs_begin_frames);
  if (software_output_device_) {
    software_output_device_->SetActive(needs_begin_frames && painting_, false);
  }
}
void OffScreenRenderWidgetHostView::SetWantsAnimateOnlyBeginFrames() {