Make checkdeps.py check third_party.

third_party/liblouis/liblouis_nacl.gyp

 # Copyright 2014 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.
 
 {
   'variables': {
     'braille_test_data_dir': '<(PRODUCT_DIR)/chromevox_test_data/braille',
     'braille_chromevox_dir': '<(PRODUCT_DIR)/resources/chromeos/chromevox/braille',
     'table_files': [
       '>!@pymod_do_main(liblouis_list_tables -D . -D src/tables -e cvox-common.cti tables.json)',
@@ skipping 30 matching lines @@
             'build_newlib': 1,
           },
           'compile_flags': [
             '-Wno-switch',
             '-Wno-unused-but-set-variable',
           ],
           'include_dirs': [
             'overrides/liblouis',
             'src/liblouis',
             '.',
+            '../..',
           ],
           'direct_dependent_settings': {
             'include_dirs': [
               'overrides',
             ],
           },
           'sources': [
             'overrides/liblouis/config.h',
             'overrides/liblouis/liblouis.h',
             'src/liblouis/compileTranslationTable.c',
@@ skipping 121 matching lines @@
               'files': [
                 '<@(table_files)',
               ],
             },
           ],
         },
       ],
     }],
   ],
 }