Revert of Create rtc::AtomicInt POD struct.

Revert of Create rtc::AtomicInt POD struct. (patchset #12 id:220001 of https://codereview.webrtc.org/1420043008/ )

Reason for revert:
Caused static initializers.

BUG=chromium:556866
TBR=tommi@webrtc.org

Original issue's description:
> Create rtc::AtomicInt POD struct.
>
> Prevents accidental non-atomic reads, increments and stores since
> "volatile int" doesn't enforce atomic usage.
>
> BUG=
> R=kwiberg@webrtc.org, tommi@webrtc.org
>
> Committed: https://crrev.com/b27f590ece487819c3d1fda400315e582fb975b6
> Cr-Commit-Position: refs/heads/master@{#10657}

TBR=kwiberg@webrtc.org,tommi@webrtc.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/3c12f4dadb969afb97468aeb1548777bf860085a
Cr-Commit-Position: refs/heads/master@{#10669}

[pbos-webrtc, 2015-11-17 11:20:42]

Created Revert of Create rtc::AtomicInt POD struct.

[commit-bot: I haz the power, 2015-11-17 11:20:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1453093002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1453093002/1

[commit-bot: I haz the power, 2015-11-17 11:21:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-17 11:21:19]

Patchset 1 (id:??) landed as
https://crrev.com/3c12f4dadb969afb97468aeb1548777bf860085a
Cr-Commit-Position: refs/heads/master@{#10669}