function getRenderedHostOrTextFromComponent(component) {
	  var rendered;
	  while (rendered = component._renderedComponent) {
	    component = rendered;
	  }
	  return component;
	}
Drill down (through composites and empty components) until we get a host or
host text component.

This is pretty polymorphic but unavoidable with the current structure we have
for `_renderedChildren`.