Add pnacl shims to the chrome build.

PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
 
 import re
 import subprocess
 import sys
 
 
 _EXCLUDED_PATHS = (
     r"^breakpad[\\\/].*",
     r"^native_client_sdk[\\\/].*",
     r"^net[\\\/]tools[\\\/]spdyshark[\\\/].*",
     r"^skia[\\\/].*",
     r"^v8[\\\/].*",
     r".*MakeFile$",
     r".+_autogen\.h$",
     r"^cc[\\\/].*",
+    r".+[\\\/]pnacl_shim\.c$",
 )
 
 
 _TEST_ONLY_WARNING = (
     'You might be calling functions intended only for testing from\n'
     'production code.  It is OK to ignore this warning if you know what\n'
     'you are doing, as the heuristics used to detect the situation are\n'
     'not perfect.  The commit queue will not block on this warning.\n'
     'Email joi@chromium.org if you have questions.')
 
@@ skipping 557 matching lines @@
   # Same for ash and chromeos.
   if any(re.search('[/_](ash|aura)', f) for f in files):
     trybots += ['linux_chromeos', 'linux_chromeos_clang:compile', 'win_aura',
                 'linux_chromeos_asan']
   else:
     if any(re.search('[/_]chromeos', f) for f in files):
       trybots += ['linux_chromeos', 'linux_chromeos_clang:compile',
                   'linux_chromeos_asan']
 
   return trybots