* Electron version: latest
* Operating system: MacOS

The TouchBar API (and MacOS in general) let's you pass an `imageNamed` param to NSImage to get the default OS image. For example: `[NSImage imageNamed:@"NSTouchBarGoUpTemplate"];` creates an NSImage with the default up chevron icon on MacOS. 

It would be pretty neat-o to allow TouchBar users to do something like this: 

```javascript
new TouchBarButton({
  icon: nativeImage.createFromMacOSNamedImage('NSTouchBarGoUpTemplate')
})
```

...and maybe that would just no-op with `nativeImage.createEmpty()` on non-MacOS platforms. 

I guess this is really bigger than just TouchBar because this API could benefit `Menu` for example as well, or anywhere else where you use `nativeImage`. 


atom/common/api/atom_api_native_image.cc
v8::Isolate* isolate, v8::Local<v8::FunctionTemplate> prototype) {
  prototype->SetClassName(mate::StringToV8(isolate, "NativeImage"));
  mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
      .SetMethod("toPNG", &NativeImage::ToPNG)
      .SetMethod("toJPEG", &NativeImage::ToJPEG)
      .SetMethod("toBitmap", &NativeImage::ToBitmap)
      .SetMethod("getBitmap", &NativeImage::GetBitmap)
      .SetMethod("getNativeHandle", &NativeImage::GetNativeHandle)
      .SetMethod("toDataURL", &NativeImage::ToDataURL)
      .SetMethod("isEmpty", &NativeImage::IsEmpty)
      .SetMethod("getSize", &NativeImage::GetSize)
      .SetMethod("setTemplateImage", &NativeImage::SetTemplateImage)
      .SetMethod("isTemplateImage", &NativeImage::IsTemplateImage)
      .SetMethod("resize", &NativeImage::Resize)
      .SetMethod("crop", &NativeImage::Crop)
      .SetMethod("getAspectRatio", &NativeImage::GetAspectRatio)
      .SetMethod("addRepresentation", &NativeImage::AddRepresentation)
      /
      .SetMethod("toPng", &NativeImage::ToPNG)
      .SetMethod("toJpeg", &NativeImage::ToJPEG);
}
}  /
}  /
namespace mate {
v8::Local<v8::Value> Converter<mate::Handle<atom::api::NativeImage>>::ToV8(
    v8::Isolate* isolate,
    const mate::Handle<atom::api::NativeImage>& val) {
  return val.ToV8();
}
bool Converter<mate::Handle<atom::api::NativeImage>>::FromV8(