Move logging CriticalSection into implementation.

Move logging CriticalSection into implementation.

Prevents including platform headers from all files that include logging.
Also removes warn_slow_logs_delay_ which adds contention to the logging
critical section.

BUG=
R=tommi@webrtc.org

Committed: https://chromium.googlesource.com/external/webrtc/+/225789d0670caf4742ba22b3a941df28d046ee4c

[pbos-webrtc, 2015-10-23 12:08:00]

TPAL woo

[pbos-webrtc, 2015-10-23 12:08:41]

The CQ bit was checked by pbos@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-23 12:08:48]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416373004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416373004/1

[tommi, 2015-10-23 12:53:31]

lgtm % nits

https://codereview.webrtc.org/1416373004/diff/1/webrtc/base/logging.cc
File webrtc/base/logging.cc (right):

https://codereview.webrtc.org/1416373004/diff/1/webrtc/base/logging.cc#newcod...
webrtc/base/logging.cc:104: // Global lock for log subsystem, only needed to
serialize access to streams_.
can you move this comment so that it's for the lock instead of the namespace?

https://codereview.webrtc.org/1416373004/diff/1/webrtc/base/logging.cc#newcod...
webrtc/base/logging.cc:106: CriticalSection log_crit_;
nit: g_log_crit or even g_log_lock

[commit-bot: I haz the power, 2015-10-23 13:01:02]

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

[commit-bot: I haz the power, 2015-10-23 13:01:03]

Dry run: This issue passed the CQ dry run.

[pbos-webrtc, 2015-10-23 13:18:32]

g_log_crit + another C++11 loop

[commit-bot: I haz the power, 2015-10-23 13:21:19]

Patchset 2 (id:??) landed as
https://crrev.com/225789d0670caf4742ba22b3a941df28d046ee4c
Cr-Commit-Position: refs/heads/master@{#10388}

[pbos-webrtc, 2015-10-23 13:21:21]

Committed patchset #2 (id:20001) manually as
225789d0670caf4742ba22b3a941df28d046ee4c (presubmit successful).