Custom ResourceResolver seems to be ignored in version 2.7+

It's the first time I open an issue on Apache JIRA. I read the guidelines but I hope I did not make mistakes.

When creating a FopFactory with a custom ResourceResolver, the resolver seems to be ignored in Apache FOP 2.7 e 2.8.

The same code apperead to work properly in Apache FOP 2.6.

ResourceResolver resolver = new ClassLoaderResourceResolver();
            FopFactoryBuilder builder = new FopFactoryBuilder(new File(".").toURI(), resolver );
            builder = builder.setConfiguration(new DefaultConfigurationBuilder().build(fopConfigStream));
            FopFactory fopFactory = builder.build(); 

Here is a proof of concept with a custom ResourceResolver loading font from the class loader when the path starts with classpath://

https://github.com/fugerit79/fop-custom-resource-resolver-poc