Avoid calling isMainThread() in the common cases when checking ScriptForbiddenScope::isScriptForbid…

Avoid calling isMainThread() in the common cases when checking ScriptForbiddenScope::isScriptForbidden().

Usually when s_scriptForbiddenCount is true we're about to crash, so check that
first then check which thread it is. This means a background thread will read
the potentially racy value of the counter, but it'll always return false when
it checks isMainThread() next.

Review-Url: https://codereview.chromium.org/2709763003
Cr-Commit-Position: refs/heads/master@{#456284}
Committed: https://chromium.googlesource.com/chromium/src/+/3b4b07ced6315a25960ca5a51dd1b7ba88de53db

[esprehn, 2017-02-21 21:58:30]

The CQ bit was checked by esprehn@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-02-21 21:59:46]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[esprehn, 2017-02-21 23:18:53]

Description was changed from

==========
Avoid calling isMainThread() in the common cases when checking
ScriptForbiddenScope::isScriptForbidden().

BUG=
==========

to

==========
Avoid calling isMainThread() in the common cases when checking
ScriptForbiddenScope::isScriptForbidden().

Usually when s_scriptForbiddenCount is true we're about to crash, so check that
first then check which thread it is. This means a background thread will read
the potentially racy value of the counter, but it'll always return false when
it checks isMainThread() next.
==========

[esprehn, 2017-02-21 23:19:07]

esprehn@chromium.org changed reviewers:
+ dglazkov@chromium.org, jbroman@chromium.org

[dglazkov, 2017-02-21 23:40:22]

lgtm

[esprehn, 2017-02-21 23:41:06]

The CQ bit was unchecked by esprehn@chromium.org

[esprehn, 2017-02-21 23:41:08]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2017-02-21 23:41:56]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-22 00:05:44]

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

[commit-bot: I haz the power, 2017-02-22 00:05:45]

Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_TIMED_OUT, no build URL)
  chromeos_daisy_chromium_compile_only_ng on master.tryserver.chromium.linux
(JOB_TIMED_OUT, no build URL)
  linux_chromium_asan_rel_ng on master.tryserver.chromium.linux (JOB_TIMED_OUT,
no build URL)
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux
(JOB_TIMED_OUT, no build URL)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_TIMED_OUT, no
build URL)

[esprehn, 2017-02-22 01:00:25]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2017-02-22 01:03:58]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-22 01:47:20]

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

[commit-bot: I haz the power, 2017-02-22 01:47:21]

Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_TIMED_OUT, no build
URL)

[esprehn, 2017-02-22 01:57:40]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2017-02-22 01:58:38]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-02-22 03:06:52]

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

[commit-bot: I haz the power, 2017-02-22 03:06:53]

Exceeded global retry quota

[esprehn, 2017-03-11 01:46:16]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2017-03-11 01:46:37]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-11 17:52:17]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1489196776596540,
"parent_rev": "a54a48cb6f59fe24dd4a4e566d42c9f059e9e242", "commit_rev":
"3b4b07ced6315a25960ca5a51dd1b7ba88de53db"}

[commit-bot: I haz the power, 2017-03-11 17:53:15]

Description was changed from

==========
Avoid calling isMainThread() in the common cases when checking
ScriptForbiddenScope::isScriptForbidden().

Usually when s_scriptForbiddenCount is true we're about to crash, so check that
first then check which thread it is. This means a background thread will read
the potentially racy value of the counter, but it'll always return false when
it checks isMainThread() next.
==========

to

==========
Avoid calling isMainThread() in the common cases when checking
ScriptForbiddenScope::isScriptForbidden().

Usually when s_scriptForbiddenCount is true we're about to crash, so check that
first then check which thread it is. This means a background thread will read
the potentially racy value of the counter, but it'll always return false when
it checks isMainThread() next.

Review-Url: https://codereview.chromium.org/2709763003
Cr-Commit-Position: refs/heads/master@{#456284}
Committed:
https://chromium.googlesource.com/chromium/src/+/3b4b07ced6315a25960ca5a51dd1...
==========

[commit-bot: I haz the power, 2017-03-11 17:53:16]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/3b4b07ced6315a25960ca5a51dd1...

[sof, 2017-03-12 06:35:09]

sigbjornf@opera.com changed reviewers:
+ sigbjornf@opera.com

[sof, 2017-03-12 06:35:09]

Could the read be made atomic to avoid (e.g.) crbug.com/700720 'noise' ?

[esprehn, 2017-03-17 15:29:32]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/2755143002/ by esprehn@chromium.org.

The reason for reverting is: meh..