Pepper: Add a X-Requested-With header to URL requests done for Pepper plugins.

ppapi/tests/test_url_loader.h

 // Copyright (c) 2012 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.
 
 #ifndef PAPPI_TESTS_TEST_URL_LOADER_H_
 #define PAPPI_TESTS_TEST_URL_LOADER_H_
 
 #include <string>
 
 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
@@ skipping 54 matching lines @@
   std::string TestTrustedCrossOriginRequest();
   std::string TestUntrustedJavascriptURLRestriction();
   std::string TestTrustedJavascriptURLRestriction();
   std::string TestUntrustedHttpRequests();
   std::string TestTrustedHttpRequests();
   std::string TestFollowURLRedirect();
   std::string TestAuditURLRedirect();
   std::string TestAbortCalls();
   std::string TestUntendedLoad();
   std::string TestPrefetchBufferThreshold();
+  std::string TestXRequestedWithHeader();
 
   const PPB_FileIOTrusted* file_io_trusted_interface_;
   const PPB_URLLoaderTrusted* url_loader_trusted_interface_;
 };
 
 #endif  // PAPPI_TESTS_TEST_URL_LOADER_H_