They were disabled during the Chromium 61 upgrade. Fix them and enable.

/cc @alespergl 
atom/common/api/atom_api_native_image.cc
mate::Arguments* args, v8::Local<v8::Value> buffer) {
  int width = 0;
  int height = 0;
  double scale_factor = 1.;
  mate::Dictionary options;
  if (args->GetNext(&options)) {
    options.Get("width", &width);
    options.Get("height", &height);
    options.Get("scaleFactor", &scale_factor);
  } else {
    /
    args->GetNext(&scale_factor);
  }
  gfx::ImageSkia image_skia;
  AddImageSkiaRep(&image_skia,
                  reinterpret_cast<unsigned char*>(node::Buffer::Data(buffer)),
                  node::Buffer::Length(buffer),
                  width,
                  height,
                  scale_factor);
  return Create(args->isolate(), gfx::Image(image_skia));
}
/
mate::Handle<NativeImage> NativeImage::CreateFromDataURL(