Revert of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread

Revert of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread (patchset #18 id:340001 of https://codereview.webrtc.org/3007473002/ )

Reason for revert:
Breaks google3 project.

Original issue's description:
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread
> 
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread. This will eventually allow us to run multiple log sessions on a single task-queue.
> 
> BUG=webrtc:8142, webrtc:8143, webrtc:8145
> 
> Review-Url: https://codereview.webrtc.org/3007473002
> Cr-Commit-Position: refs/heads/master@{#19666}
> Committed: https://chromium.googlesource.com/external/webrtc/+/f33cee7534f0469330b6b7aa57f84eec4b082598

TBR=terelius@webrtc.org,nisse@webrtc.org,eladalon@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:8142, webrtc:8143, webrtc:8145
Review-Url: https://codereview.webrtc.org/3010143002
Cr-Commit-Position: refs/heads/master@{#19672}
Committed: https://chromium.googlesource.com/external/webrtc/+/3eac8002db8fdf5124026d5377a1f3ec1d16bb0d

[charujain, 2017-09-04 18:06:07]

The CQ bit was checked by charujain@webrtc.org

[charujain, 2017-09-04 18:06:07]

Created Revert of Make RtcEventLogImpl to use a TaskQueue instead of a
helper-thread

[commit-bot: I haz the power, 2017-09-04 18:06:11]

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, 2017-09-04 18:06:15]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1504548367270150, "parent_rev":
"d56ef8085718e15c497b0d9c60baa1a4640420fa", "commit_rev":
"3eac8002db8fdf5124026d5377a1f3ec1d16bb0d"}

[commit-bot: I haz the power, 2017-09-04 18:06:20]

Description was changed from

==========
Revert of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread
(patchset #18 id:340001 of https://codereview.webrtc.org/3007473002/ )

Reason for revert:
Breaks google3 project.

Original issue's description:
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread
> 
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread. This will
eventually allow us to run multiple log sessions on a single task-queue.
> 
> BUG=webrtc:8142, webrtc:8143, webrtc:8145
> 
> Review-Url: https://codereview.webrtc.org/3007473002
> Cr-Commit-Position: refs/heads/master@{#19666}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/f33cee7534f0469330b6b7aa5...

TBR=terelius@webrtc.org,nisse@webrtc.org,eladalon@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:8142, webrtc:8143, webrtc:8145
==========

to

==========
Revert of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread
(patchset #18 id:340001 of https://codereview.webrtc.org/3007473002/ )

Reason for revert:
Breaks google3 project.

Original issue's description:
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread
> 
> Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread. This will
eventually allow us to run multiple log sessions on a single task-queue.
> 
> BUG=webrtc:8142, webrtc:8143, webrtc:8145
> 
> Review-Url: https://codereview.webrtc.org/3007473002
> Cr-Commit-Position: refs/heads/master@{#19666}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/f33cee7534f0469330b6b7aa5...

TBR=terelius@webrtc.org,nisse@webrtc.org,eladalon@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:8142, webrtc:8143, webrtc:8145

Review-Url: https://codereview.webrtc.org/3010143002
Cr-Commit-Position: refs/heads/master@{#19672}
Committed:
https://chromium.googlesource.com/external/webrtc/+/3eac8002db8fdf5124026d537...
==========

[commit-bot: I haz the power, 2017-09-04 18:06:21]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/3eac8002db8fdf5124026d537...

[eladalon, 2017-09-05 12:32:35]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/3005153002/ by eladalon@webrtc.org.

The reason for reverting is: I will fix and reland..