Update from https://crrev.com/318214

tools/lsan/PRESUBMIT.py

-# Copyright 2013 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.
-
-"""
-See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
-for more details on the presubmit API built into depot_tools.
-"""
-
-import re
-
-def CheckChange(input_api, output_api):
-  errors = []
-
-  for f in input_api.AffectedFiles():
-    if not f.LocalPath().endswith('suppressions.txt'):
-      continue
-    for line_num, line in enumerate(f.NewContents()):
-      line = line.strip()
-      if line.startswith('#') or not line:
-        continue
-      if not line.startswith('leak:'):
-        errors.append('"%s" should be "leak:..." in %s line %d' %
-                      (line, f.LocalPath(), line_num))
-  if errors:
-    return [output_api.PresubmitError('\n'.join(errors))]
-  return []
-
-def CheckChangeOnUpload(input_api, output_api):
-  return CheckChange(input_api, output_api)
-
-def CheckChangeOnCommit(input_api, output_api):
-  return CheckChange(input_api, output_api)