Revert of Refactored incoming bitrate estimator.

Revert of Refactored incoming bitrate estimator. (patchset #8 id:140001 of https://codereview.webrtc.org/2917873002/ )

Reason for revert:
Caused failure in vice test

Original issue's description:
> Refactored incoming bitrate estimator.
> 
> BUG=webrtc:7746
> 
> Review-Url: https://codereview.webrtc.org/2917873002
> Cr-Commit-Position: refs/heads/master@{#18478}
> Committed: https://chromium.googlesource.com/external/webrtc/+/5fc8bf8b87495c225f5060760fa9d967b8dc9f9e

TBR=philipel@webrtc.org,terelius@webrtc.org,stefan@webrtc.org,tschumim@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7746

[tschumim, 2017-06-07 18:48:36]

The CQ bit was checked by tschumim@google.com

[tschumim, 2017-06-07 18:48:37]

Created Revert of Refactored incoming bitrate estimator.

[commit-bot: I haz the power, 2017-06-07 18:48:47]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-06-07 18:48:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-07 18:48:49]

No L-G-T-M from a valid reviewer yet.
CQ run can only be started once the patch has received an L-G-T-M from a full
committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,_not_ a
full super star committer.
Committers are members of the group "project-webrtc-committers".
Note that this has nothing to do with OWNERS files.