[debug] use best effort coverage when enabling precise coverage.

[debug] use best effort coverage when enabling precise coverage.

We used to clear invocation counts when enabling precise coverage.
This is not necessary, and we could continue to use the existing
invocation counts on the heap. The old behavior can be achieved
by explicitly resetting the counts by polling coverage data.

R=jgruber@chromium.org,caseq@chromium.org
BUG=v8:5808
Review-Url: https://codereview.chromium.org/2768453002
Cr-Commit-Position: refs/heads/master@{#43964}
Committed: https://chromium.googlesource.com/v8/v8/+/ed93e7c27b2c3f2ddd995fdc3a40b35341232e9f

[jgruber, 2017-03-21 08:22:27]

lgtm

[Yang, 2017-03-21 08:29:03]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2017-03-21 08:29:08]

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, 2017-03-21 08:55:45]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1490084943527690,
"parent_rev": "48e08319cad468885d8d29af5a17cb9e761e5dfa", "commit_rev":
"ed93e7c27b2c3f2ddd995fdc3a40b35341232e9f"}

[commit-bot: I haz the power, 2017-03-21 08:55:51]

Description was changed from

==========
[debug] use best effort coverage when enabling precise coverage.

We used to clear invocation counts when enabling precise coverage.
This is not necessary, and we could continue to use the existing
invocation counts on the heap. The old behavior can be achieved
by explicitly resetting the counts by polling coverage data.

R=jgruber@chromium.org,caseq@chromium.org
BUG=v8:5808
==========

to

==========
[debug] use best effort coverage when enabling precise coverage.

We used to clear invocation counts when enabling precise coverage.
This is not necessary, and we could continue to use the existing
invocation counts on the heap. The old behavior can be achieved
by explicitly resetting the counts by polling coverage data.

R=jgruber@chromium.org,caseq@chromium.org
BUG=v8:5808

Review-Url: https://codereview.chromium.org/2768453002
Cr-Commit-Position: refs/heads/master@{#43964}
Committed:
https://chromium.googlesource.com/v8/v8/+/ed93e7c27b2c3f2ddd995fdc3a40b353412...
==========

[commit-bot: I haz the power, 2017-03-21 08:55:51]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/ed93e7c27b2c3f2ddd995fdc3a40b353412...