Add disabled_warnings arg to RunPylint() and use the default pylintrc file by default.

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 depot tools.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into depot_tools.
 """
 
 
 def CommonChecks(input_api, output_api, tests_to_black_list):
   results = []
   results.extend(input_api.canned_checks.CheckOwners(input_api, output_api))
   black_list = list(input_api.DEFAULT_BLACK_LIST) + [
       r'^cpplint\.py$',
       r'^cpplint_chromium\.py$',
       r'^python_bin[\/\\].+',
       r'^site-packages-py[0-9]\.[0-9][\/\\].+',
       r'^svn_bin[\/\\].+',
       r'^testing_support[\/\\]_rietveld[\/\\].+']
+  disabled_warnings = [
+    'R0401',  # Cyclic import
+    'W0613',  # Unused argument
+  ]
   results.extend(input_api.canned_checks.RunPylint(
       input_api,
       output_api,
       white_list=[r'.*\.py$'],
-      black_list=black_list))
+      black_list=black_list,
+      disabled_warnings=disabled_warnings))
 
   # TODO(maruel): Make sure at least one file is modified first.
   # TODO(maruel): If only tests are modified, only run them.
   results.extend(input_api.canned_checks.RunUnitTestsInDirectory(
       input_api,
       output_api,
       'tests',
       whitelist=[r'.*test\.py$'],
       blacklist=tests_to_black_list))
   return results
@@ skipping 59 matching lines @@
 
 
 def CheckChangeOnCommit(input_api, output_api):
   output = []
   output.extend(CommonChecks(input_api, output_api, []))
   output.extend(input_api.canned_checks.CheckDoNotSubmit(
       input_api,
       output_api))
   output.extend(RunGitClTests(input_api, output_api))
   return output