Update Native Client Authors to be Chromium Authors for the code moved from the

ppapi/native_client/tests/ppapi_geturl/nacl_file_main.cc

-// Copyright (c) 2011 The Native Client Authors. All rights reserved.
+// 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.
 //
 // Tests nacl_file library.
 //
 
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ skipping 193 matching lines @@
   // Run the test from the main thread again, this time competing with
   // the other threads.
   info.rseed = rand_r(&rseed);
   test_nacl_file_thread(&info);
   // Give the threads a chance to start racing before joining them.
   usleep(100000);
   for (int i = 0; i < kNumThreads; ++i) {
     pthread_join(thread[i], NULL);
   }
 }