code: private void addReturnTypeIfMissing(
        PolymerClassDefinition cls, String getterPropName, JSTypeExpression jsType) {
      Node classMembers = NodeUtil.getClassMembers(cls.definition);
      Node getter = NodeUtil.getFirstGetterMatchingKey(classMembers, getterPropName);
      if (getter != null) {
        JSDocInfo info = NodeUtil.getBestJSDocInfo(getter);
        if (info == null || !info.hasReturnType()) {
          JSDocInfoBuilder builder = JSDocInfoBuilder.maybeCopyFrom(info);
          builder.recordReturnType(jsType);
          getter.setJSDocInfo(builder.build());
        }
      }
    }
docs: Adds return type information to class getters