Node name = IR.name(PROTECTOR_FN);
name.putBooleanProp(Node.IS_CONSTANT_NAME, true);
Node var = IR.var(name);
// Add "@noalias" so we can strip the method when AliasExternals is enabled.
JSDocInfoBuilder builder = new JSDocInfoBuilder(false);
builder.recordNoAlias();
var.setJSDocInfo(builder.build(var));
CompilerInput input = compiler.getSynthesizedExternsInput();
input.getAstRoot(compiler).addChildrenToBack(var);
compiler.reportCodeChange();
}