Reland of Verify sender ssrc when receiving rtcp target bitrate (patchset #1 id:1 of https://codereview.webrtc.org/3005633002/ )

Reason for revert:
Landed fix in upstream project.

Original issue's description:
> Revert of Verify sender ssrc when receiving rtcp target bitrate (patchset #3 id:40001 of https://codereview.webrtc.org/3000373002/ )
>
> Reason for revert:
> Might be the root cause of an internal test failure.
>
> Original issue's description:
> > Verify sender ssrc when receiving rtcp target bitrate
> >
> > BUG=webrtc:8137
> >
> > Review-Url: https://codereview.webrtc.org/3000373002
> > Cr-Commit-Position: refs/heads/master@{#19524}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/a7a4beb419612e16e781e143f9bc0c812e044f75
>
> TBR=danilchap@webrtc.org,sprang@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:8137
>
> Review-Url: https://codereview.webrtc.org/3005633002
> Cr-Commit-Position: refs/heads/master@{#19529}
> Committed: https://chromium.googlesource.com/external/webrtc/+/95a64ca8aa3ab20692bf8fbb24c7ea7b72abb0a6

TBR=danilchap@webrtc.org,zhihuang@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:8137

Review-Url: https://codereview.webrtc.org/3006683002
Cr-Original-Commit-Position: refs/heads/master@{#19557}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: b32aaf97bd73d16604e9e85221f2dbc4a9433e61
3 files changed