Re-add common.gypi to help fix closure_compilation.

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 depot_tools.
 """
 
@@ skipping 1229 matching lines @@
       if bad_pattern.search(line) and not good_pattern.search(line):
         errors.append('%s:%d' % (f.LocalPath(), linenum))
 
   if errors:
     return [output_api.PresubmitError(
       'These lines create anonymous variables that need to be named:',
       items=errors)]
   return []
 
 
-def _CheckCygwinShell(input_api, output_api):
-  source_file_filter = lambda x: input_api.FilterSourceFile(
-      x, white_list=(r'.+\.(gyp|gypi)$',))
-  cygwin_shell = []
-
-  for f in input_api.AffectedSourceFiles(source_file_filter):
-    for linenum, line in f.ChangedContents():
-      if 'msvs_cygwin_shell' in line:
-        cygwin_shell.append(f.LocalPath())
-        break
-
-  if cygwin_shell:
-    return [output_api.PresubmitError(
-      'These files should not use msvs_cygwin_shell (the default is 0):',
-      items=cygwin_shell)]
-  return []
-
-
 def _CheckUserActionUpdate(input_api, output_api):
   """Checks if any new user action has been added."""
   if any('actions.xml' == input_api.os_path.basename(f) for f in
          input_api.LocalPaths()):
     # If actions.xml is already included in the changelist, the PRESUBMIT
     # for actions.xml will do a more complete presubmit check.
     return []
 
   file_filter = lambda f: f.LocalPath().endswith(('.cc', '.mm'))
   action_re = r'[^a-zA-Z]UserMetricsAction\("([^"]*)'
@@ skipping 713 matching lines @@
   results.extend(_CheckForInvalidIfDefinedMacros(input_api, output_api))
   results.extend(_CheckFlakyTestUsage(input_api, output_api))
   results.extend(_CheckAddedDepsHaveTargetApprovals(input_api, output_api))
   results.extend(
       input_api.canned_checks.CheckChangeHasNoTabs(
           input_api,
           output_api,
           source_file_filter=lambda x: x.LocalPath().endswith('.grd')))
   results.extend(_CheckSpamLogging(input_api, output_api))
   results.extend(_CheckForAnonymousVariables(input_api, output_api))
-  results.extend(_CheckCygwinShell(input_api, output_api))
   results.extend(_CheckUserActionUpdate(input_api, output_api))
   results.extend(_CheckNoDeprecatedCSS(input_api, output_api))
   results.extend(_CheckNoDeprecatedJS(input_api, output_api))
   results.extend(_CheckParseErrors(input_api, output_api))
   results.extend(_CheckForIPCRules(input_api, output_api))
   results.extend(_CheckForCopyrightedCode(input_api, output_api))
   results.extend(_CheckForWindowsLineEndings(input_api, output_api))
   results.extend(_CheckSingletonInHeaders(input_api, output_api))
   results.extend(_CheckNoDeprecatedCompiledResourcesGYP(input_api, output_api))
   results.extend(_CheckPydepsNeedsUpdating(input_api, output_api))
@@ skipping 258 matching lines @@
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api,
       output_api,
       json_url='http://chromium-status.appspot.com/current?format=json'))
 
   results.extend(input_api.canned_checks.CheckChangeHasBugField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   return results