[heap] Filter out nullptr when registering externally referenced objects

[heap] Filter out nullptr when registering externally referenced objects

Ideally they are already filtered on the embedder side. Sometimes
howevever, embedders end up with a Local<T> pointing to a nullptr
object. In this case the best way to filter this is right at the
beginning of the registration process.

BUG=chromium:713667
Review-Url: https://codereview.chromium.org/2836013003
Cr-Commit-Position: refs/heads/master@{#44844}
Committed: https://chromium.googlesource.com/v8/v8/+/64e06641ebeef8bf86174c9465b5dbc002d73ca4

[Michael Lippautz, 2017-04-25 11:09:43]

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

[commit-bot: I haz the power, 2017-04-25 11:09:49]

Dry run: CQ is trying da patch.

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

[Hannes Payer (out of office), 2017-04-25 11:18:41]

hpayer@chromium.org changed reviewers:
+ hpayer@chromium.org

[Hannes Payer (out of office), 2017-04-25 11:18:41]

lgtm

[commit-bot: I haz the power, 2017-04-25 11:37:53]

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

[commit-bot: I haz the power, 2017-04-25 11:37:54]

Dry run: This issue passed the CQ dry run.

[Michael Lippautz, 2017-04-25 11:46:04]

The CQ bit was checked by mlippautz@chromium.org

[commit-bot: I haz the power, 2017-04-25 11:46:13]

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, 2017-04-25 11:47:28]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493120764789010, "parent_rev":
"e480b2b29d89530479b418341653217e6d464f6b", "commit_rev":
"64e06641ebeef8bf86174c9465b5dbc002d73ca4"}

[commit-bot: I haz the power, 2017-04-25 11:47:36]

Description was changed from

==========
[heap] Filter out nullptr when registering externally referenced objects

Ideally they are already filtered on the embedder side. Sometimes
howevever, embedders end up with a Local<T> pointing to a nullptr
object. In this case the best way to filter this is right at the
beginning of the registration process.

BUG=chromium:713667
==========

to

==========
[heap] Filter out nullptr when registering externally referenced objects

Ideally they are already filtered on the embedder side. Sometimes
howevever, embedders end up with a Local<T> pointing to a nullptr
object. In this case the best way to filter this is right at the
beginning of the registration process.

BUG=chromium:713667

Review-Url: https://codereview.chromium.org/2836013003
Cr-Commit-Position: refs/heads/master@{#44844}
Committed:
https://chromium.googlesource.com/v8/v8/+/64e06641ebeef8bf86174c9465b5dbc002d...
==========

[commit-bot: I haz the power, 2017-04-25 11:47:37]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/64e06641ebeef8bf86174c9465b5dbc002d...