[heap] Remove Heap::TracePath* functions.

[heap] Remove Heap::TracePath* functions.

The functions do not work correctly with concurrent sweeper and they
do not take weak references into account.

The latter is a fundamental problem for this tracing approach.

BUG=

Review-Url: https://codereview.chromium.org/2707433002
Cr-Commit-Position: refs/heads/master@{#43284}
Committed: https://chromium.googlesource.com/v8/v8/+/9e187ea91ba7e455ffd7cd584bb6426b0fa82ef4

[ulan, 2017-02-17 14:11:47]

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

[ulan, 2017-02-17 14:11:48]

PTAL.

[Michael Lippautz, 2017-02-17 14:13:45]

On 2017/02/17 14:11:48, ulan wrote:
> PTAL.

lgtm, although I found them rather useful for debugging purposes.

I can patch them in when I need though.

[ulan, 2017-02-17 14:22:21]

On 2017/02/17 14:13:45, Michael Lippautz wrote:
> On 2017/02/17 14:11:48, ulan wrote:
> > PTAL.
> 
> lgtm, although I found them rather useful for debugging purposes.
> 
> I can patch them in when I need though.

For debugging I patch the marker to save the visited edges. That gives more
trustworthy retaining path. In the long-term we probably want something like
that landed behind a flag.

[ulan, 2017-02-17 14:22:29]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2017-02-17 14:22:41]

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, 2017-02-17 15:06:59]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487341349573820, "parent_rev":
"a84b23399ec4a15cd03192cd168079d2eac5a9da", "commit_rev":
"9e187ea91ba7e455ffd7cd584bb6426b0fa82ef4"}

[commit-bot: I haz the power, 2017-02-17 15:07:03]

Description was changed from

==========
[heap] Remove Heap::TracePath* functions.

The functions do not work correctly with concurrent sweeper and they
do not take weak references into account.

The latter is a fundamental problem for this tracing approach.

BUG=
==========

to

==========
[heap] Remove Heap::TracePath* functions.

The functions do not work correctly with concurrent sweeper and they
do not take weak references into account.

The latter is a fundamental problem for this tracing approach.

BUG=

Review-Url: https://codereview.chromium.org/2707433002
Cr-Commit-Position: refs/heads/master@{#43284}
Committed:
https://chromium.googlesource.com/v8/v8/+/9e187ea91ba7e455ffd7cd584bb6426b0fa...
==========

[commit-bot: I haz the power, 2017-02-17 15:07:04]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/9e187ea91ba7e455ffd7cd584bb6426b0fa...