Make sure ScriptWrappables have a wrapper before calling setReference()

Make sure ScriptWrappables have a wrapper before calling setReference()

Failure to check for a valid wrapper before calling setReference (and
then into v8::Isolate::SetReference) results in NULL handles being
visited (and crashing) during V8 GC.

BUG=610340, 612206
Committed: https://crrev.com/eb23b41351d08e79e222870c70d05151585fed26
Cr-Commit-Position: refs/heads/master@{#393986}

[adamk, 2016-05-16 19:12:06]

adamk@chromium.org changed reviewers:
+ haraken@chromium.org

[adamk, 2016-05-16 19:12:07]

I haven't been able to reproduce this crash, but it's a top crasher on Canary.

The shape of a repro would be to have a wrapper for, e.g., a V8SVGLength which
is a tear off of some SVGElement that doesn't itself have a wrapper. But I
haven't been able to find a way to create such a case. Nevertheless,
https://codereview.chromium.org/1683493003 clearly removed the containsWrapper
check that this patch re-adds.

[haraken, 2016-05-16 22:30:48]

Thanks, LGTM

[adamk, 2016-05-16 22:33:28]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2016-05-16 22:34:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1981013002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1981013002/1

[commit-bot: I haz the power, 2016-05-16 23:59:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-17 00:01:13]

Description was changed from

==========
Make sure ScriptWrappables have a wrapper before calling setReference()

Failure to check for a valid wrapper before calling setReference (and
then into v8::Isolate::SetReference) results in NULL handles being
visited (and crashing) during V8 GC.

BUG=610340,612206
==========

to

==========
Make sure ScriptWrappables have a wrapper before calling setReference()

Failure to check for a valid wrapper before calling setReference (and
then into v8::Isolate::SetReference) results in NULL handles being
visited (and crashing) during V8 GC.

BUG=610340,612206

Committed: https://crrev.com/eb23b41351d08e79e222870c70d05151585fed26
Cr-Commit-Position: refs/heads/master@{#393986}
==========

[commit-bot: I haz the power, 2016-05-17 00:01:14]

Patchset 1 (id:??) landed as
https://crrev.com/eb23b41351d08e79e222870c70d05151585fed26
Cr-Commit-Position: refs/heads/master@{#393986}