Fix and enable lint checks.

PRESUBMIT.py

 # Copyright 2015 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.
 
 """Presubmit script for pdfium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
 LINT_FILTERS = [
   '-build/c++11',
   '-build/include',
   '-build/include_order',
   '-build/include_what_you_use',
   '-build/namespaces',
   '-build/storage_class',
-  '-readability/braces',
   '-readability/casting',
   '-readability/fn_size',
-  '-readability/function',
-  '-readability/inheritance',
-  '-readability/multiline_comment',
-  '-readability/multiline_string',
-  '-readability/namespace',
   '-readability/todo',
   '-readability/utf8',
   '-runtime/arrays',
   '-runtime/casting',
   '-runtime/explicit',
   '-runtime/int',
   '-runtime/printf',
   '-runtime/references',
   '-runtime/threadsafe_fn',
   '-whitespace/indent',
   '-whitespace/line_length',
 ]
 
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results += input_api.canned_checks.CheckPatchFormatted(input_api, output_api)
   results += input_api.canned_checks.CheckChangeLintsClean(
       input_api, output_api, None, LINT_FILTERS)
   return results