@Override
    protected Processor doBuild(DeployState deployState, TreeConfigProducer<AnyConfigProducer> ancestor, Element processorElement) {
        ChainedComponentModelBuilder modelBuilder = new ChainedComponentModelBuilder(processorElement);
        return new Processor(modelBuilder.build());
    }
Builds a processor from XML.

@author  bratseth
@since   5.1.6
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/chains/processing/DomProcessorBuilder.java