cc: Turn on presubmit cpplint warnings

cc/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 cc.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into gcl.
 """
 
 import re
 
 CC_SOURCE_FILES=(r'^cc/.*\.(cc|h)$',)
 CC_PERF_TEST =(r'^.*_perftest.*\.(cc|h)$',)
 
+def CheckChangeLintsClean(input_api, output_api):
+  import cpplint
+  cpplint._cpplint_state.ResetErrorCounts()  # reset global state
+  source_filter = lambda x: input_api.FilterSourceFile(
+    x, white_list=CC_SOURCE_FILES, black_list=None)
+  files = [f.AbsoluteLocalPath() for f in
+           input_api.AffectedSourceFiles(source_filter)]
+  level = 1  # strict, but just warn
+
+  for file_name in files:
+    cpplint.ProcessFile(file_name, level)
+
+  if not cpplint._cpplint_state.error_count:
+    return []
+
+  return [output_api.PresubmitPromptWarning(
+    'Changelist failed cpplint.py check.')]
+
 def CheckAsserts(input_api, output_api, white_list=CC_SOURCE_FILES, black_list=None):
   black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
   source_file_filter = lambda x: input_api.FilterSourceFile(x, white_list, black_list)
 
   assert_files = []
   notreached_files = []
 
   for f in input_api.AffectedSourceFiles(source_file_filter):
     contents = input_api.ReadFile(f, 'rb')
     # WebKit ASSERT() is not allowed.
@@ skipping 35 matching lines @@
     return [output_api.PresubmitError(
       'These files spam the console log with printf/fprintf:',
       items=printf)]
   return []
 
 
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results += CheckAsserts(input_api, output_api)
   results += CheckSpamLogging(input_api, output_api, black_list=CC_PERF_TEST)
+  results += CheckChangeLintsClean(input_api, output_api)
   return results
 
 def GetPreferredTrySlaves(project, change):
   return [
     'linux_layout_rel',
     ]