I do a lot of HTML generation just with JavaScript and am finding myself creating `index.html` files that have code that looks like this:

     <!DOCTYPE html><html><head><script src="index.js"></script></head><body></body></html>

It would be nice to be able to do:

     browserWindow.loadHTML('<!DOCTYPE html><html><head><script src="index.js"></script></head><body></body></html>');

It would be even more awesome to do:

     browserWindow.loadScript(pathToScript);

I tried to use the `preload` option for `BrowserWindow` and using `loadURL('about:blank')`, but this has an unintended side effect of not allowing you to reference other script or CSS files using relative paths.

What do you think about proposed feature?
atom/browser/api/atom_api_web_contents.cc
if (!IsOffScreen())
    return;
  auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
  if (osr_rwhv)
    osr_rwhv->SetFrameRate(frame_rate);
}
int WebContents::GetFrameRate() const {
  if (!IsOffScreen())
    return 0;
  const auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
  return osr_rwhv ? osr_rwhv->GetFrameRate() : 0;
}
void WebContents::Invalidate() {
  if (IsOffScreen()) {
    auto* osr_rwhv = static_cast<OffScreenRenderWidgetHostView*>(
      web_contents()->GetRenderWidgetHostView());
    if (osr_rwhv)
      osr_rwhv->Invalidate();
  } else {
    const auto window = owner_window();
    if (window)
      window->Invalidate();
  }
}
void WebContents::SetZoomLevel(double level) {