Revert of Remove audio/video distinction for probe packets. (patchset #2 id:20001 of https://codereview.webrtc.org/2061193002/ )

Reason for revert:
Revert this because it broke the google3 import build.
http://webrtc-buildbot-master.mtv.corp.google.com:21000/builders/WebRTC%20google3%20Importer%20%28Shem%20TOT%29/builds/67/steps/blaze_regular_tests/logs/stdio

Original issue's description:
> Remove audio/video distinction for probe packets.
>
> Allows detecting large-enough audio packets as part of a probe,
> speculative fix for a rampup-time regression in M50. These packets are
> accounted on the send side when probing.
>
> BUG=webrtc:5985
> R=mflodman@webrtc.org, philipel@webrtc.org
>
> Committed: https://crrev.com/a7d88d38448f6a5677a017562765ab505b89d468
> Cr-Commit-Position: refs/heads/master@{#13210}

TBR=mflodman@webrtc.org,philipel@webrtc.org,pbos@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5985

Review-Url: https://codereview.webrtc.org/2086633002
Cr-Original-Commit-Position: refs/heads/master@{#13221}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 17bde8c96ee8b5a7e496a7dc98828b84f9756925
34 files changed