Fix data race in blink::WorkerMessagingProxy::reportException

Fix data race in blink::WorkerMessagingProxy::reportException

Also make it impossible to access WorkerThread::workerGlobalScope
on a wrong thread at least from outside the class

BUG=520012, 460445
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=200821

[kinuko, 2015-08-19 06:48:24]

kinuko@chromium.org changed reviewers:
+ hiroshige@chromium.org, toyoshim@chromium.org

[kinuko, 2015-08-19 06:50:19]

Could either of you review?

[hiroshige, 2015-08-19 10:33:15]

lgtm. Thanks for fixing!

Tested the case in Issue 460445 ~20 times and didn't see TSAN warnings
corresponding to this issue.

[kinuko, 2015-08-19 11:19:59]

On 2015/08/19 10:33:15, hiroshige (ooo zombie) wrote:
> lgtm. Thanks for fixing!
> 
> Tested the case in Issue 460445 ~20 times and didn't see TSAN warnings
> corresponding to this issue.

Thanks for verifying!

[kinuko, 2015-08-19 11:20:04]

The CQ bit was checked by kinuko@chromium.org

[commit-bot: I haz the power, 2015-08-19 11:20:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1305453003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1305453003/1

[commit-bot: I haz the power, 2015-08-19 12:27:40]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=200821