Add C++ wrappers for output parameters.

ppapi/examples/url_loader/streaming.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This example shows how to use the URLLoader in streaming mode (reading to
 // memory as data comes over the network). This example uses PostMessage between
 // the plugin and the url_loader.html page in this directory to start the load
 // and to communicate the result.
 //
 // The other mode is to stream to a file instead. For that mode, call
@@ skipping 64 matching lines @@
 
 void MyInstance::StartRequest(const std::string& url) {
   content_.clear();
 
   pp::URLRequestInfo request(this);
   request.SetURL(url);
   request.SetMethod("GET");
 
   loader_ = pp::URLLoader(this);
   loader_.Open(request,
-               factory_.NewRequiredCallback(&MyInstance::OnOpenComplete));
+               factory_.NewCallback(&MyInstance::OnOpenComplete));
 }
 
 void MyInstance::OnOpenComplete(int32_t result) {
   if (result != PP_OK) {
     ReportResponse("URL could not be requested");
     return;
   }
 
   response_ = loader_.GetResponseInfo();
 
@@ skipping 67 matching lines @@
 };
 
 namespace pp {
 
 // Factory function for your specialization of the Module object.
 Module* CreateModule() {
   return new MyModule();
 }
 
 }  // namespace pp