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

/cc @alespergl 
atom/common/api/atom_api_native_image.cc
v8::Isolate* isolate, const char* buffer, size_t length) {
  gfx::Image image = gfx::ImageFrom1xJPEGEncodedData(
      reinterpret_cast<const unsigned char*>(buffer), length);
  return Create(isolate, image);
}
/
mate::Handle<NativeImage> NativeImage::CreateFromPath(
    v8::Isolate* isolate, const base::FilePath& path) {
  base::FilePath image_path = NormalizePath(path);
#if defined(OS_WIN)
  if (image_path.MatchesExtension(FILE_PATH_LITERAL(".ico"))) {
    return mate::CreateHandle(isolate,
                              new NativeImage(isolate, image_path));
  }
#endif
  gfx::ImageSkia image_skia;
  PopulateImageSkiaRepsFromPath(&image_skia, image_path);
  gfx::Image image(image_skia);
  mate::Handle<NativeImage> handle = Create(isolate, image);
#if defined(OS_MACOSX)
  if (IsTemplateFilename(image_path))
    handle->SetTemplateImage(true);
#endif
  return handle;
}
/
mate::Handle<NativeImage> NativeImage::CreateFromBuffer(