Fix BUILD.gn files and add presubmit step

PRESUBMIT.py

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 198 matching lines @@
           not exclusion_pattern.search(line)):
         problems.append(
           '%s:%d\n    %s' % (local_path, line_number, line.strip()))
 
   if problems:
     return [output_api.PresubmitPromptOrNotify(_TEST_ONLY_WARNING, problems)]
   else:
     return []
 
 
+def _CheckMissingFiles(input_api, output_api):
+  """Runs verify_source_deps.py to ensure no files were added that are not in
+  GN.
+  """
+  # We need to wait until we have an input_api object and use this
+  # roundabout construct to import checkdeps because this file is
+  # eval-ed and thus doesn't have __file__.
+  original_sys_path = sys.path
+  try:
+    sys.path = sys.path + [input_api.os_path.join(
+        input_api.PresubmitLocalPath(), 'tools')]
+    from verify_source_deps import missing_gn_files, missing_gyp_files
+  finally:
+    # Restore sys.path to what it was before.
+    sys.path = original_sys_path
+
+  gn_files = missing_gn_files()
+  gyp_files = missing_gyp_files()
+  results = []
+  if gn_files:
+    results.append(output_api.PresubmitError(
+        "You added one or more source files but didn't update the\n"
+        "corresponding BUILD.gn files:\n",
+        gn_files))
+  if gyp_files:
+    results.append(output_api.PresubmitError(
+        "You added one or more source files but didn't update the\n"
+        "corresponding gyp files:\n",
+        gyp_files))
+  return results
+
+
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
   results.extend(input_api.canned_checks.CheckOwners(
       input_api, output_api, source_file_filter=None))
   results.extend(input_api.canned_checks.CheckPatchFormatted(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckGenderNeutral(
       input_api, output_api))
   results.extend(_V8PresubmitChecks(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(
       _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api))
   results.extend(
       _CheckNoInlineHeaderIncludesInNormalHeaders(input_api, output_api))
+  results.extend(_CheckMissingFiles(input_api, output_api))
   return results
 
 
 def _SkipTreeCheck(input_api, output_api):
   """Check the env var whether we want to skip tree check.
      Only skip if include/v8-version.h has been updated."""
   src_version = 'include/v8-version.h'
   if not input_api.AffectedSourceFiles(
       lambda file: file.LocalPath() == src_version):
     return False
   return input_api.environ.get('PRESUBMIT_TREE_CHECK') == 'skip'
 
 
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   if not _SkipTreeCheck(input_api, output_api):
     results.extend(input_api.canned_checks.CheckTreeIsOpen(
         input_api, output_api,
         json_url='http://v8-status.appspot.com/current?format=json'))
   return results