Enable cpplint for webrtc/audio and webrtc/call, and fix all uncovered cpplint errors.

BUG=webrtc:5268,webrtc:5273
TESTED=Fixed issues reported by:
find webrtc/audio -type f -name *.cc -o -name *.h | xargs cpplint.py
find webrtc/call -type f -name *.cc -o -name *.h | xargs cpplint.py
followed by 'git cl presubmit'.

R=kjellander@webrtc.org, pbos@webrtc.org

Review URL: https://codereview.webrtc.org/1483323002 .

Cr-Commit-Position: refs/heads/master@{#10853}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 5258549..06a1c4a 100755
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -16,6 +16,8 @@
 
 # Directories that will be scanned by cpplint by the presubmit script.
 CPPLINT_DIRS = [
+  'webrtc/audio',
+  'webrtc/call',
   'webrtc/video_engine',
 ]