maybe I'm wrong, but I think that if we don't add this condition, we won't call `fetchImageData` in the case of our bug ?

I think updateTime and the icon url won't have changed ?

So I think we should have:

```javascript
if (descriptor.updateTime == oldDescriptor.updateTime &&
   descriptor.icon == oldDescriptor.icon &&
   oldDescriptor.renderedIcon) {
   this.descriptor.renderedIcon = oldDescriptor.renderedIcon;
} else {
  this.oldRenderedIcon = oldDescriptor.renderedIcon;
  this.fetchImageData();
}
```

Do I miss something ?