Make Isolate::AddDetachedContext GC safe

Make Isolate::AddDetachedContext GC safe

CopyFixedArrayAndGrow can trigger GC, which can clean up
previous detached contexts, so storing the length of the
FixedArray across the allocation is unsafe.

BUG=v8:6282
Review-Url: https://codereview.chromium.org/2857633002
Cr-Commit-Position: refs/heads/master@{#45038}
Committed: https://chromium.googlesource.com/v8/v8/+/63a40cae7c23c36e8b9c13f52a19a6f262f40d81

[Jakob Kummerow, 2017-05-02 14:18:33]

jkummerow@chromium.org changed reviewers:
+ cbruni@chromium.org

[Jakob Kummerow, 2017-05-02 14:18:34]

Camillo: PTAL.

Hannes: FYI.

[Camillo Bruni, 2017-05-02 14:20:40]

lgtm

[Jakob Kummerow, 2017-05-02 14:33:14]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2017-05-02 14:33:17]

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, 2017-05-02 15:06:32]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1493735594938880,
"parent_rev": "5a766b4401b262aa7dcf9e32e37157ddb8a07b28", "commit_rev":
"63a40cae7c23c36e8b9c13f52a19a6f262f40d81"}

[commit-bot: I haz the power, 2017-05-02 15:06:39]

Description was changed from

==========
Make Isolate::AddDetachedContext GC safe

CopyFixedArrayAndGrow can trigger GC, which can clean up
previous detached contexts, so storing the length of the
FixedArray across the allocation is unsafe.

BUG=v8:6282
==========

to

==========
Make Isolate::AddDetachedContext GC safe

CopyFixedArrayAndGrow can trigger GC, which can clean up
previous detached contexts, so storing the length of the
FixedArray across the allocation is unsafe.

BUG=v8:6282

Review-Url: https://codereview.chromium.org/2857633002
Cr-Commit-Position: refs/heads/master@{#45038}
Committed:
https://chromium.googlesource.com/v8/v8/+/63a40cae7c23c36e8b9c13f52a19a6f262f...
==========

[commit-bot: I haz the power, 2017-05-02 15:06:39]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/63a40cae7c23c36e8b9c13f52a19a6f262f...