code: private Node makeReadOnlySetter(String propName, String qualifiedPath) {
      String setterName = "_set" + propName.substring(0, 1).toUpperCase() + propName.substring(1);
      Node fnNode = IR.function(IR.name(""), IR.paramList(IR.name(propName)), IR.block());
      compiler.reportChangeToChangeScope(fnNode);
      Node exprResNode =
          IR.exprResult(IR.assign(NodeUtil.newQName(compiler, qualifiedPath + setterName), fnNode));
  
      JSDocInfoBuilder info = new JSDocInfoBuilder(true);
      // This is overriding a generated function which was added to the interface in
      // {@code createExportsAndExterns}.
      info.recordOverride();
      exprResNode.getFirstChild().setJSDocInfo(info.build());
  
      return exprResNode;
    }
docs: Adds the generated setter for a readonly property.
  
  @see https://www.polymer-project.org/0.8/docs/devguide/properties.html#read-only