Fix license headers in a number of files

ppapi/native_client/src/trusted/plugin/plugin_unittest.cc

-// Copyright 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.
+// 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.
 
 // Unit tests for ppGoogleNaClPlugin
 
 #include <stdio.h>
 
 #include "native_client/src/include/nacl_string.h"
 #include "native_client/src/trusted/plugin/nexe_arch.h"
 #include "native_client/src/trusted/plugin/dylib_unittest.h"
 
 // Verify that the ISA string returned by the plugin is the correct one for
@@ skipping 37 matching lines @@
   }
 
   if (success) {
     printf("PASS\n");
     return 0;
   } else {
     printf("FAIL\n");
     return 1;
   }
 }