Use new common tools in Python scripts

PRESUBMIT.py

 # Copyright (c) 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.
 
 
 """Top-level presubmit script for Skia.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
@@ skipping 28 matching lines @@
     if len(contents) > 1 and contents[-1:] != '\n':
       eof_files.append(f.LocalPath())
 
   if eof_files:
     return [output_api.PresubmitPromptWarning(
       'These files should end in a newline character:',
       items=eof_files)]
   return []
 
 
+def _PythonChecks(input_api, output_api):
+  """Run checks on any modified Python files."""
+  pylint_disabled_warnings = (
+      'F0401',  # Unable to import.
+      'E0611',  # No name in module.
+      'W0232',  # Class has no __init__ method.
+      'E1002',  # Use of super on an old style class.
+      'W0403',  # Relative import used.
+      'R0201',  # Method could be a function.
+      'E1003',  # Using class name in super.
+      'W0613',  # Unused argument.
+  )
+  # Run Pylint on only the modified python files. Unfortunately it still runs
+  # Pylint on the whole file instead of just the modified lines.
+  affected_python_files = []
+  for affected_file in input_api.AffectedSourceFiles(None):
+    affected_file_path = affected_file.LocalPath()
+    if affected_file_path.endswith('.py'):
+      affected_python_files.append(affected_file_path)
+  return input_api.canned_checks.RunPylint(
+      input_api, output_api,
+      disabled_warnings=pylint_disabled_warnings,
+      white_list=affected_python_files)
+
+
 def _CommonChecks(input_api, output_api):
   """Presubmit checks common to upload and commit."""
   results = []
   sources = lambda x: (x.LocalPath().endswith('.h') or
                        x.LocalPath().endswith('.gypi') or
                        x.LocalPath().endswith('.gyp') or
                        x.LocalPath().endswith('.py') or
                        x.LocalPath().endswith('.sh') or
                        x.LocalPath().endswith('.cpp'))
   results.extend(
       _CheckChangeHasEol(
           input_api, output_api, source_file_filter=sources))
+  results.extend(_PythonChecks(input_api, output_api))
   return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
   """Presubmit checks for the change on upload.
 
   The following are the presubmit checks:
   * Check change has one and only one EOL.
   """
   results = []
@@ skipping 111 matching lines @@
       # An owner created the CL that is an automatic LGTM.
       lgtm_from_owner = True
 
     messages = issue_properties.get('messages')
     if messages:
       for message in messages:
         if (message['sender'] in PUBLIC_API_OWNERS and
             'lgtm' in message['text'].lower()):
           # Found an lgtm in a message from an owner.
           lgtm_from_owner = True
-          break;
+          break
 
   if not lgtm_from_owner:
     results.append(
         output_api.PresubmitError(
             'Since the CL is editing public API, you must have an LGTM from '
             'one of: %s' % str(PUBLIC_API_OWNERS)))
   return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
   """Presubmit checks for the change on commit.
 
   The following are the presubmit checks:
   * Check change has one and only one EOL.
   * Ensures that the Skia tree is open in
     http://skia-tree-status.appspot.com/. Shows a warning if it is in 'Caution'
     state and an error if it is in 'Closed' state.
   """
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(
       _CheckTreeStatus(input_api, output_api, json_url=(
           SKIA_TREE_STATUS_URL + '/banner-status?format=json')))
   results.extend(_CheckLGTMsForPublicAPI(input_api, output_api))
   results.extend(_CheckOwnerIsInAuthorsFile(input_api, output_api))
   return results