Fix lint errors to enable stricter PyLint rules

tools-webrtc/vim/webrtc.ycm_extra_conf.py

 # Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 # Autocompletion config for YouCompleteMe in WebRTC. This is just copied from
 # tools/vim in chromium with very minor modifications.
@@ skipping 43 matching lines @@
 #   * This has only been tested on gPrecise.
 
 
 import os
 import os.path
 import shlex
 import subprocess
 import sys
 
 # Flags from YCM's default config.
-_default_flags = [
+_DEFAULT_FLAGS = [
   '-DUSE_CLANG_COMPLETER',
   '-std=c++11',
   '-x',
   'c++',
 ]
 
-_header_alternates = ('.cc', '.cpp', '.c', '.mm', '.m')
+_HEADER_ALTERNATES = ('.cc', '.cpp', '.c', '.mm', '.m')
 
-_extension_flags = {
+_EXTENSION_FLAGS = {
   '.m': ['-x', 'objective-c'],
   '.mm': ['-x', 'objective-c++'],
 }
 
 def PathExists(*args):
   return os.path.exists(os.path.join(*args))
 
 
 def FindWebrtcSrcFromFilename(filename):
   """Searches for the root of the WebRTC checkout.
@@ skipping 211 matching lines @@
   # doesn't know about some used warning options, which causes compilation
   # warnings (and errors, because of '-Werror');
   additional_flags.append('-Wno-unknown-warning-option')
 
   sys.path.append(os.path.join(webrtc_root, 'tools', 'vim'))
   from ninja_output import GetNinjaOutputDirectory
   out_dir = GetNinjaOutputDirectory(webrtc_root)
 
   basename, extension = os.path.splitext(filename)
   if extension == '.h':
-    candidates = [basename + ext for ext in _header_alternates]
+    candidates = [basename + ext for ext in _HEADER_ALTERNATES]
   else:
     candidates = [filename]
 
   clang_line = None
   buildable_extension = extension
   for candidate in candidates:
     clang_line = GetClangCommandLineFromNinjaForSource(out_dir, candidate)
     if clang_line:
       buildable_extension = os.path.splitext(candidate)[1]
       break
 
-  additional_flags += _extension_flags.get(buildable_extension, [])
+  additional_flags += _EXTENSION_FLAGS.get(buildable_extension, [])
 
   if not clang_line:
     # If ninja didn't know about filename or it's companion files, then try a
     # default build target. It is possible that the file is new, or build.ninja
     # is stale.
     clang_line = GetClangCommandLineFromNinjaForSource(
         out_dir, GetDefaultSourceFile(webrtc_root, filename))
 
   if not clang_line:
     return additional_flags
@@ skipping 14 matching lines @@
   """
   abs_filename = os.path.abspath(filename)
   webrtc_root = FindWebrtcSrcFromFilename(abs_filename)
   clang_flags = GetClangOptionsFromNinjaForFilename(webrtc_root, abs_filename)
 
   # If clang_flags could not be determined, then assume that was due to a
   # transient failure. Preventing YCM from caching the flags allows us to try to
   # determine the flags again.
   should_cache_flags_for_file = bool(clang_flags)
 
-  final_flags = _default_flags + clang_flags
+  final_flags = _DEFAULT_FLAGS + clang_flags
 
   return {
     'flags': final_flags,
     'do_cache': should_cache_flags_for_file
   }