Bugfix to stop chrome from crashing.

Adds a nullptr check to prevent a rare crash when starting or stopping an RtcEventLog.

BUG=webrtc:4741, chromium:581788
Committed: https://crrev.com/20834ca806595a4f46c838f1e69c32d0c836fb12
Cr-Commit-Position: refs/heads/master@{#11490}

[ivoc, 2016-02-04 12:48:51]

Description was changed from

==========
Bugfix to stop chrome from crashing.

BUG=webrtc:4741,chromium:581788
==========

to

==========
Adds a nullptr check to prevent a rare crash when starting or stopping an
RtcEventLog.

BUG=webrtc:4741,chromium:581788
==========

[ivoc, 2016-02-04 12:48:51]

ivoc@webrtc.org changed reviewers:
+ solenberg@webrtc.org

[ivoc, 2016-02-04 12:50:48]

Hi Fredrik,

This is exactly the same bugfix as the one you reviewed earlier, but for ToT.

[the sun, 2016-02-04 12:51:49]

lgtm

[ivoc, 2016-02-04 12:57:55]

The CQ bit was checked by ivoc@webrtc.org

[commit-bot: I haz the power, 2016-02-04 12:58:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1666843003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1666843003/1

[commit-bot: I haz the power, 2016-02-04 13:00:05]

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

[commit-bot: I haz the power, 2016-02-04 13:00:05]

Try jobs failed on following builders:
  linux_compile_dbg on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/linux_compile_dbg/build...)

[ivoc, 2016-02-04 13:32:15]

The CQ bit was checked by ivoc@webrtc.org

[ivoc, 2016-02-04 13:32:15]

The patchset sent to the CQ was uploaded after l-g-t-m from solenberg@webrtc.org
Link to the patchset: https://codereview.webrtc.org/1666843003/#ps20001 (title:
"Added namespace.")

[commit-bot: I haz the power, 2016-02-04 13:32:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1666843003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1666843003/20001

[commit-bot: I haz the power, 2016-02-04 14:33:40]

Description was changed from

==========
Adds a nullptr check to prevent a rare crash when starting or stopping an
RtcEventLog.

BUG=webrtc:4741,chromium:581788
==========

to

==========
Adds a nullptr check to prevent a rare crash when starting or stopping an
RtcEventLog.

BUG=webrtc:4741,chromium:581788
==========

[commit-bot: I haz the power, 2016-02-04 14:33:41]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-02-04 14:33:44]

Description was changed from

==========
Adds a nullptr check to prevent a rare crash when starting or stopping an
RtcEventLog.

BUG=webrtc:4741,chromium:581788
==========

to

==========
Adds a nullptr check to prevent a rare crash when starting or stopping an
RtcEventLog.

BUG=webrtc:4741,chromium:581788

Committed: https://crrev.com/20834ca806595a4f46c838f1e69c32d0c836fb12
Cr-Commit-Position: refs/heads/master@{#11490}
==========

[commit-bot: I haz the power, 2016-02-04 14:33:45]

Patchset 2 (id:??) landed as
https://crrev.com/20834ca806595a4f46c838f1e69c32d0c836fb12
Cr-Commit-Position: refs/heads/master@{#11490}