* 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
if (image_.HasRepresentation(gfx::Image::kImageRepSkia)) {
    isolate()->AdjustAmountOfExternalAllocatedMemory(
      - image_.ToImageSkia()->bitmap()->computeSize64());
  }
}
#if defined(OS_WIN)
HICON NativeImage::GetHICON(int size) {
  auto iter = hicons_.find(size);
  if (iter != hicons_.end())
    return iter->second.get();
  
  if (!hicon_path_.empty()) {
    hicons_[size] = std::move(ReadICOFromPath(size, hicon_path_));
    return hicons_[size].get();
  }
  
  if (image_.IsEmpty())
    return NULL;
  hicons_[size] = std::move(
      IconUtil::CreateHICONFromSkBitmap(image_.AsBitmap()));
  return hicons_[size].get();
}
#endif
v8::Local<v8::Value> NativeImage::ToPNG(mate::Arguments* args) {