deps: cherry-pick 15c0c3a8ba and 43e2fb1c3d from upstream V8

[Flarna]

These changes avoid a busy wait loop in V8 CPU Profiler thread for windows (except for short intervals).

It would be good if this is also backported to Node.js v9 and LTS releases as this busy loop effectively disallows the use of cpu-profiler in windows production setups.

Original commit message 15c0c3a8ba:

[profiler] use Sleep() on windows for long profile intervals.

See nodejs/diagnostics#170

[email protected]

Change-Id: Iecc3bb27707b0d2afbb23fd9823d5cd4d725be6e
Reviewed-on: https://chromium-review.googlesource.com/931102
Reviewed-by: Franziska Hinkelmann <[email protected]>
Commit-Queue: Yang Guo <[email protected]>
Cr-Commit-Position: refs/heads/master@{#51466}

Original commit message 43e2fb1c3d:

[profiler] fix sleeping on windows for long intervals.
[email protected]

Change-Id: I5717db794fc797e7c3b0b8f122ddb6dc0702a99e
Reviewed-on: https://chromium-review.googlesource.com/941126
Reviewed-by: Franziska Hinkelmann <[email protected]>
Commit-Queue: Yang Guo <[email protected]>
Cr-Commit-Position: refs/heads/master@{#51755}

Refs: nodejs/diagnostics#170
Refs: v8/v8@15c0c3a
Refs: v8/v8@43e2fb1

Checklist

• commit message follows commit guidelines

[targos]

@nodejs/v8 Could they be backported upstream?

[ofrobots]

Opened upstream merge request bug (https://bugs.chromium.org/p/v8/issues/detail?id=7535) as per guide.

[Flarna]

Grrr, seems I have read the wrong guideline...

@ofrobots Thanks for creating the upstream merge request!

@targos commit 15c0c3a8ba is included in 6.6. but 43e2fb1c3d not therefore V8 team should really merge 43e2fb1c3d at least to 6.6.
If I understand #19201 correct it's planned to use 6.6 (or newer) in Node v10. Therefore backport to 6.6. should be enough; no need to have this in master already now via 6.5 or a cherry pick.

nodejs/diagnostics#170 (comment) indicated to me that backports will be not done therefore I created this PR.

If I understood the v8 maintenance guide correct it's needed to create separate backport PRs for Node 9, 8, 6 and 4. But I assume this should wait until this PR is closed.

[ofrobots]

If I understood the v8 maintenance guide correct it's needed to create separate backport PRs for Node 9, 8, 6 and 4. But I assume this should wait until this PR is closed.

Let's wait to see what merges get approved upstream. This PR may be needed yet.

If the fixes are easy to cherry-pick for the previous node versions, then a separate backport may not even need to be opened, and the release team would take care of back-porting.

[ofrobots]

If I understand #19201 correct it's planned to use 6.6 (or newer) in Node v10. Therefore backport to 6.6. should be enough; no need to have this in master already now via 6.5 or a cherry pick.

Until #19201 lands, let's assume that we need the merges to V8 6.5 as well.

[Flarna]

I have seen that above v8 fix is available via 6.5.254.37 (and 6.6.346.10) so it seems this cherry-pick PR is not needed.
But I'm not sure how to proceed to get new V8 into master + cherry-pick fix to older nodejs version.
Should I simply create PRs for this or is this done "automagically" somehow via some other mechanism I don't know?

[ofrobots]

Hi @Flarna. You should retarget this PR to Node 9. The release team will take care of back-porting and releasing on older versions beyond that. If the cherry-pick does not land cleanly on older versions, then they will ping you to request a manual back-port, as necessary.

[Flarna]

@ofrobots ok thanks. I will do a separate PR for Node 9.
V8 updates on master seem to happen anyway (e.g. #19303).