[heap] Clear slots for map space when writing zap values

[heap] Clear slots for map space when writing zap values

Pointer updating requires the all slots to be valid. If we write zap values in
the sweeper we need to filter out invalid slots before.

BUG=chromium:625748
LOG=N
R=ulan@chromium.org

Committed: https://crrev.com/9a4132aad254894df4e8e7f41bb8ceefd266d721
Cr-Commit-Position: refs/heads/master@{#37538}

[ulan, 2016-07-05 16:35:04]

lgtm

[Michael Lippautz, 2016-07-05 16:35:25]

The CQ bit was checked by mlippautz@chromium.org

[commit-bot: I haz the power, 2016-07-05 16:35:35]

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, 2016-07-05 16:58:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-05 17:00:19]

Description was changed from

==========
[heap] Clear slots for map space when writing zap values

Pointer updating requires the all slots to be valid. If we write zap values in
the sweeper we need to filter out invalid slots before.

BUG=chromium:625748
LOG=N
R=ulan@chromium.org
==========

to

==========
[heap] Clear slots for map space when writing zap values

Pointer updating requires the all slots to be valid. If we write zap values in
the sweeper we need to filter out invalid slots before.

BUG=chromium:625748
LOG=N
R=ulan@chromium.org

Committed: https://crrev.com/9a4132aad254894df4e8e7f41bb8ceefd266d721
Cr-Commit-Position: refs/heads/master@{#37538}
==========

[commit-bot: I haz the power, 2016-07-05 17:00:20]

Patchset 1 (id:??) landed as
https://crrev.com/9a4132aad254894df4e8e7f41bb8ceefd266d721
Cr-Commit-Position: refs/heads/master@{#37538}