### Feature request

`customButtonsOnHover` fixes a lot of issues with drag and `pointer` styles, but my app currently uses `hidden-inset` so this setting changes the position of the buttons. I'd suggest `customButtonsOnHover` either be an option outside of `titleBarStyle` that respects `titleBarStyle`s values ('hiddenInset' or `hidden') or the addition of a `customButtonsOnHoverInset`.

As a separate note, the docs for `customButtonsOnHover` currently specify it's a Boolean type, but it's a string value.
shell/browser/api/electron_api_base_window.cc
v8::Handle<v8::Value> val,
                     electron::TaskbarHost::ThumbarButton* out) {
    gin::Dictionary dict(isolate);
    if (!gin::ConvertFromV8(isolate, val, &dict))
      return false;
    dict.Get("click", &(out->clicked_callback));
    dict.Get("tooltip", &(out->tooltip));
    dict.Get("flags", &out->flags);
    return dict.Get("icon", &(out->icon));
  }
};
}  
#endif
namespace electron {
namespace api {
namespace {
v8::Local<v8::Value> ToBuffer(v8::Isolate* isolate, void* val, int size) {
  auto buffer = node::Buffer::Copy(isolate, static_cast<char*>(val), size);
  if (buffer.IsEmpty())
    return v8::Null(isolate);
  else
    return buffer.ToLocalChecked();
}
}  
BaseWindow::BaseWindow(v8::Isolate* isolate,
                       const gin_helper::Dictionary& options)