Reland: Prevent data race in MessageQueue.

Reland: Prevent data race in MessageQueue.

The CL prevents a data race in MessageQueue where the variable "ss_" is
modified without a lock while sometimes read inside a lock.

Also thread annotations have been added to the MessageQueue class.

This was already reviewed and landed in https://codereview.webrtc.org/1675923002/
but failed in Chromium GN builds due to sharedexclusivelock.cc not being
compiled in these builds. This changed in https://codereview.webrtc.org/1712773003/
so the reland should work fine now.

BUG=webrtc:5496
Committed: https://crrev.com/9ccedc38f6ba113a95cfcd2db59112051ab11160
Cr-Commit-Position: refs/heads/master@{#11758}

[joachim, 2016-02-23 23:54:44]

jbauch@webrtc.org changed reviewers:
+ pthatcher@webrtc.org

[joachim, 2016-02-23 23:54:45]

Ptal

[pthatcher1, 2016-02-25 06:48:51]

lgtm

[joachim, 2016-02-25 08:16:18]

The CQ bit was checked by jbauch@webrtc.org

[commit-bot: I haz the power, 2016-02-25 08:16:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1729893002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1729893002/1

[commit-bot: I haz the power, 2016-02-25 09:15:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-02-25 09:15:10]

Description was changed from

==========
Reland: Prevent data race in MessageQueue.

The CL prevents a data race in MessageQueue where the variable "ss_" is
modified without a lock while sometimes read inside a lock.

Also thread annotations have been added to the MessageQueue class.

This was already reviewed and landed in
https://codereview.webrtc.org/1675923002/
but failed in Chromium GN builds due to sharedexclusivelock.cc not being
compiled in these builds. This changed in
https://codereview.webrtc.org/1712773003/
so the reland should work fine now.

BUG=webrtc:5496
==========

to

==========
Reland: Prevent data race in MessageQueue.

The CL prevents a data race in MessageQueue where the variable "ss_" is
modified without a lock while sometimes read inside a lock.

Also thread annotations have been added to the MessageQueue class.

This was already reviewed and landed in
https://codereview.webrtc.org/1675923002/
but failed in Chromium GN builds due to sharedexclusivelock.cc not being
compiled in these builds. This changed in
https://codereview.webrtc.org/1712773003/
so the reland should work fine now.

BUG=webrtc:5496

Committed: https://crrev.com/9ccedc38f6ba113a95cfcd2db59112051ab11160
Cr-Commit-Position: refs/heads/master@{#11758}
==========

[commit-bot: I haz the power, 2016-02-25 09:15:11]

Patchset 1 (id:??) landed as
https://crrev.com/9ccedc38f6ba113a95cfcd2db59112051ab11160
Cr-Commit-Position: refs/heads/master@{#11758}