Enable cpplint and fix cpplint errors in webrtc/*audio

PRESUBMIT.py

 # Copyright (c) 2012 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.
 
 import json
 import os
 import re
 import subprocess
 import sys
 
 
 # Directories that will be scanned by cpplint by the presubmit script.
 CPPLINT_DIRS = [
   'webrtc/api',
   'webrtc/audio',
   'webrtc/call',
+  'webrtc/common_audio',
   'webrtc/common_video',
   'webrtc/examples',
   'webrtc/modules/audio_mixer',
   'webrtc/modules/bitrate_controller',
   'webrtc/modules/congestion_controller',
   'webrtc/modules/pacing',
   'webrtc/modules/remote_bitrate_estimator',
   'webrtc/modules/rtp_rtcp',
   'webrtc/modules/video_coding',
   'webrtc/modules/video_processing',
   'webrtc/tools',
   'webrtc/video',

[kwiberg-webrtc, 2017/03/08 12:55:12]

Drive-by comment: Any chance we could use a blacklist instead, so that the
default is to be scanned?

(Not saying it should be done in this CL, just that it would probably be a good
idea.)

[oprypin_webrtc, 2017/03/08 13:22:03]

You could bring this up in the parent issue
https://bugs.chromium.org/p/webrtc/issues/detail?id=5149
As it progresses, it will make more and more sense to do this.

[kwiberg-webrtc, 2017/03/08 13:25:01]

Done. Thanks!

 ]
 
 # These filters will always be removed, even if the caller specifies a filter
 # set, as they are problematic or broken in some way.
 #
 # Justifications for each filter:
 # - build/c++11         : Rvalue ref checks are unreliable (false positives),
 #                         include file and feature blacklists are
 #                         google3-specific.
 # - whitespace/operators: Same as above (doesn't seem sufficient to eliminate
@@ skipping 517 matching lines @@
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   results.extend(_CheckChangeHasBugField(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasTestField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api, output_api,
       json_url='http://webrtc-status.appspot.com/current?format=json'))
   return results