Properly protect state variable by locking

Properly protect state variable by locking

R=posciak@chromium.org, wuchengli@chromium.org
BUG=none
TEST=play h264 html5 video

Committed: https://crrev.com/107a32f15d16f36e56fcdea0b4bcb6ab4b2b7316
Cr-Commit-Position: refs/heads/master@{#324405}

[kcwu, 2015-03-30 08:42:38]

just one line fix. PTAL

[Pawel Osciak, 2015-03-30 08:59:57]

lgtm, although perhaps we should CQ this after branch, I went over the code and
don't see a reason why this would cause problems, but just in case.

And we should test with video tests, apprtc does not use vavda.

[kcwu, 2015-04-09 08:43:43]

On 2015/03/30 08:59:57, Pawel Osciak wrote:
> lgtm, although perhaps we should CQ this after branch, I went over the code
and
> don't see a reason why this would cause problems, but just in case.
> 
> And we should test with video tests, apprtc does not use vavda.

Tested playing h264 html5 video and looks good. Ready to CQ.

[kcwu, 2015-04-09 08:43:51]

The CQ bit was checked by kcwu@chromium.org

[commit-bot: I haz the power, 2015-04-09 08:44:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1048773002/1

[commit-bot: I haz the power, 2015-04-09 09:52:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-09 09:52:49]

Patchset 1 (id:??) landed as
https://crrev.com/107a32f15d16f36e56fcdea0b4bcb6ab4b2b7316
Cr-Commit-Position: refs/heads/master@{#324405}