/** Compute a manifest for all RPC policy files seen so far. */
 private String generateManifest(LinkerContext context) {
   StringBuilder sb = new StringBuilder();
   sb.append("# Module " + context.getModuleName() + "\n");
   sb.append("# RPC service class, partial path of RPC policy file\n");
   sb.append(manifestBody.toString());
   return sb.toString();
 }
  @Override
  protected EmittedArtifact emitSelectionScript(
      TreeLogger logger, LinkerContext context, ArtifactSet artifacts)
      throws UnableToCompleteException {

    DefaultTextOutput out = new DefaultTextOutput(true);

    // Emit the selection script.
    // this for 'real browsers' to load the script
    // we don't need this.
    /*
    String bootstrap = generateSelectionScript(logger, context, artifacts);
    bootstrap = context.optimizeJavaScript(logger, bootstrap);
    out.print(bootstrap);
    out.newlineOpt();
    */

    // we need a ref to the top level window
    //  it is referenced in the closure below
    out.print("var $_window = this;");
    out.newlineOpt();

    // this is a hack to make backwards compatible
    out.print("var __defineParser__ = function(){};");
    out.newlineOpt();

    // Emit the module's JS a closure.
    out.newlineOpt();
    out.print("(function () {");
    out.newlineOpt();
    out.print("var $gwt_version = \"" + About.getGwtVersionNum() + "\";");
    out.newlineOpt();
    out.print("var $wnd = $_window;");
    out.newlineOpt();
    out.print("var $doc = $wnd.document;");
    out.newlineOpt();
    out.print("var $moduleName, $moduleBase;");
    out.newlineOpt();
    out.print("var $stats = $wnd.__gwtStatsEvent ? function(a) {$wnd.__gwtStatsEvent(a)} : null;");
    out.newlineOpt();

    // Find the single CompilationResult
    Set<CompilationResult> results = artifacts.find(CompilationResult.class);
    if (results.size() != 1) {
      logger.log(
          TreeLogger.ERROR,
          "The module must have exactly one distinct"
              + " permutation when using the "
              + getDescription()
              + " Linker.",
          null);
      throw new UnableToCompleteException();
    }
    CompilationResult result = results.iterator().next();

    out.print("var $strongName = '" + result.getStrongName() + "';");
    out.newlineOpt();

    String[] js = result.getJavaScript();
    if (js.length != 1) {
      logger.log(
          TreeLogger.ERROR,
          "The module must not have multiple fragments when using the "
              + getDescription()
              + " Linker.",
          null);
      throw new UnableToCompleteException();
    }

    out.print(js[0]);

    // Generate the call to tell the bootstrap code that we're ready to go.
    out.newlineOpt();

    // the original code setup an "onScriptLoad" event.
    // Here we just do it
    out.print("gwtOnLoad();");

    out.newlineOpt();
    out.print("})();");
    out.newlineOpt();

    return emitString(logger, out.toString(), context.getModuleName() + ".nocache.js");
  }