Scripts should not care about closed tree when committing.

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 40 matching lines @@
 
 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(_V8PresubmitChecks(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 src/version.cc has been updated."""
+  src_version = 'src/version.cc'
+  FilterFile = lambda file: file.LocalPath() == src_version
+  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))
-  results.extend(input_api.canned_checks.CheckTreeIsOpen(
-      input_api, output_api,
-      json_url='http://v8-status.appspot.com/current?format=json'))
+  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