Make checkdeps.py check third_party.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 477 matching lines @@
 
     'src/third_party/requests/src':
       Var('chromium_git') + '/external/github.com/kennethreitz/requests.git' + '@' + 'f172b30356d821d180fa4ecfa3e71c7274a32de4',
 
   },
 }
 
 
 include_rules = [
   # Everybody can use some things.
+  # NOTE: THIS HAS TO STAY IN SYNC WITH third_party/DEPS which disallows these.
   '+base',
   '+build',
   '+ipc',
 
   # Everybody can use headers generated by tools/generate_library_loader.
   '+library_loaders',
 
   '+testing',
   '+third_party/icu/source/common/unicode',
   '+third_party/icu/source/i18n/unicode',
   '+url',
 ]
 
 
 # checkdeps.py shouldn't check include paths for files in these dirs:
 skip_child_includes = [
   'breakpad',
-  'delegate_execute',
-  'metro_driver',
   'native_client_sdk',
-  'o3d',
+  'out',
   'sdch',
   'skia',
   'testing',
-  'third_party',
   'v8',
   'win8',
 ]
 
 
 hooks = [
   {
     # This clobbers when necessary (based on get_landmines.py). It must be the
     # first hook so that other things that get/generate into the output
     # directory will not subsequently be clobbered.
@@ skipping 258 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]