Drop NaCl support for posting stdout/stderr to JS.

ppapi/native_client/tests/nacl_browser/inbrowser_test_runner/nacl.scons

 # -*- python -*-
 # 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.
 
 import json
 import posixpath
 
 Import('env')
 
@@ skipping 20 matching lines @@
                             WriteManifestList)[0]
   # Scons does not track the dependency of nmf_list_js on exe_list, so
   # we must always recreate nmf_list_js when it is used.
   env.AlwaysBuild(nmf_list_js)
 
   node = env.PPAPIBrowserTester(
       '%s.out' % test_name, url='test_runner.html',
       nmf_names=exe_list,
       files=[env.File('test_runner.html')] + test_files,
       map_files=[('nmf_test_list.js', nmf_list_js)],
-      test_args=[('parallel', int(parallel))],
-      osenv=['NACL_EXE_STDOUT=DEBUG_ONLY:dev://postmessage',
-             'NACL_EXE_STDERR=DEBUG_ONLY:dev://postmessage'])
+      test_args=[('parallel', int(parallel))])
 
   # Disabled on Valgrind because of multiple nexes.
   # TODO(eugenis): enable when Valgrind learns to autodetect the nexe name
   env.AddNodeToTestSuite(node, ['chrome_browser_tests'], test_name,
                          disable_irt_suffix=True,
                          is_broken=env.PPAPIBrowserTesterIsBroken() or
                                    env.Bit('running_on_valgrind') or
   # inbrowser_test_runner_parallel is flaky on 32 bit windows
   # (maybe http://code.google.com/p/chromium/issues/detail?id=120355 ?)
                                    parallel)
 
 if not env.Bit('tests_use_irt'):
   Return()
 
 exe_list = env['TESTS_TO_RUN_INBROWSER']
 AddTest(env, 'run_inbrowser_test_runner', exe_list, parallel=False)
 AddTest(env, 'run_inbrowser_test_runner_parallel', exe_list, parallel=True)