First patch set uses a script attached in an issue comment:
https://bugs.chromium.org/p/webrtc/issues/detail?id=5118#c24
This discards the boilerplate prefix of WEBRTC_TRACE log strings, but it appears to be discarded anyway by all users.
Second patch set removes the header and makes small fixes to four of the log messages.
BUG=webrtc:5118
Review-Url: https://codereview.webrtc.org/2958273002
Cr-Commit-Position: refs/heads/master@{#18941}