[heap] Implement simple marking in the concurrent marking thread.

[heap] Implement simple marking in the concurrent marking thread.

The concurrent marker uses ObjectVisitor to iterate pointers in objects
and local marking bitmaps to keep track of visited objects.

To keep it simple for now, I removed support for multiple tasks
and canceling unfinished tasks.

BUG=chromium:694255
Review-Url: https://codereview.chromium.org/2732053002
Cr-Commit-Position: refs/heads/master@{#43618}
Committed: https://chromium.googlesource.com/v8/v8/+/a3923ce210c305fda4ec3f4d97f5a55f99e47b89

[ulan, 2017-03-06 18:56:43]

Description was changed from

==========
[heap] Implement simple marking in the concurrent marking thread.

The concurrent marker uses ObjectVisitor to iterate pointers in objects
and local marking bitmaps to keep track of visited objects.

BUG=chromium:694255
==========

to

==========
[heap] Implement simple marking in the concurrent marking thread.

The concurrent marker uses ObjectVisitor to iterate pointers in objects
and local marking bitmaps to keep track of visited objects.

To keep it simple for now, I removed support for multiple tasks
and canceling unfinished tasks.

BUG=chromium:694255
==========

[ulan, 2017-03-06 18:57:29]

ulan@chromium.org changed reviewers:
+ hpayer@chromium.org, mlippautz@chromium.org

[ulan, 2017-03-06 18:57:30]

ptal

[Michael Lippautz, 2017-03-06 19:02:41]

lgtm

[Hannes Payer (out of office), 2017-03-06 19:45:25]

lgtm

[ulan, 2017-03-06 19:45:28]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2017-03-06 19:45:31]

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, 2017-03-06 20:46:41]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1488829528337150,
"parent_rev": "1338ae97ded61c7d7315d9736d4c442979951bb7", "commit_rev":
"a3923ce210c305fda4ec3f4d97f5a55f99e47b89"}

[commit-bot: I haz the power, 2017-03-06 20:46:47]

Description was changed from

==========
[heap] Implement simple marking in the concurrent marking thread.

The concurrent marker uses ObjectVisitor to iterate pointers in objects
and local marking bitmaps to keep track of visited objects.

To keep it simple for now, I removed support for multiple tasks
and canceling unfinished tasks.

BUG=chromium:694255
==========

to

==========
[heap] Implement simple marking in the concurrent marking thread.

The concurrent marker uses ObjectVisitor to iterate pointers in objects
and local marking bitmaps to keep track of visited objects.

To keep it simple for now, I removed support for multiple tasks
and canceling unfinished tasks.

BUG=chromium:694255

Review-Url: https://codereview.chromium.org/2732053002
Cr-Commit-Position: refs/heads/master@{#43618}
Committed:
https://chromium.googlesource.com/v8/v8/+/a3923ce210c305fda4ec3f4d97f5a55f99e...
==========

[commit-bot: I haz the power, 2017-03-06 20:46:48]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/a3923ce210c305fda4ec3f4d97f5a55f99e...